National Health and Nutrition

Examination Survey: Plan

and Operations, 1999–2010

Series 1, Number 56 August 2013
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Zipf G, Chiappa M, Porter KS, et al. National Health and Nutrition Examination

Survey: Plan and operations, 1999–2010. National Center for Health Statistics.

Vital Health Stat 1(56). 2013.

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Series 1, Number 56

National Health and

Nutrition Examination

Survey: Plan and

Operations, 1999–2010

Program and Collection Procedures

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Hyattsville, Maryland

August 2013

DHHS Publication No. 2013–1332
National Center for Health Statistics

Charles J. Rothwell, M.S., Acting Director

Jennifer H. Madans, Ph.D., Associate Director for Science

Division of Health and Nutrition Examination Surveys

Kathryn S. Porter, M.D., M.S., Director
Contents
 

Acknowledgments .......................................................................................... v 
 

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 
 

Introduction ............................................................................................... 1 
 

History of NHANES ...................................................................................... 1 
 

Survey Planning and Sample Design ........................................................................... 3 
 

Planning Process ........................................................................................ 3 
 

Sample Design........................................................................................... 3 
 

Demographic Domains and Oversampling..................................................................... 4 
 

Sample Weights.......................................................................................... 4 
 

Ethical, Privacy, and Confidentiality Considerations............................................................... 4 
 

Ethics Review Board...................................................................................... 4 
 

Informed Consent ........................................................................................ 5 
 

Field Operations ........................................................................................... 6 
 

Schedules ............................................................................................... 6 
 

Advance Arrangements .................................................................................... 6 
 

Staffing and Training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 
 

Opening the Field Office .................................................................................. 8 
 

Mobile Examination Center ................................................................................ 8 
 

Remuneration............................................................................................ 9 
 

Household Interview ........................................................................................ 9 
 

Screener ............................................................................................... 10 
 

Relationship Questionnaire ................................................................................ 10 
 

Sample Person Questionnaire .............................................................................. 10 
 

Family Questionnaire .................................................................................... 10 
 

Household Water Collection Component ..................................................................... 11 
 

MEC Examinations and Interviews ........................................................................... 11 
 

MEC Examination Components ............................................................................ 11 
 

Interviews in the MEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 
 

MEC Biospecimen Collection................................................................................ 16 
 

MEC Laboratory Team ................................................................................... 16 
 

Biospecimen Collection................................................................................... 16 
 

Oral Glucose Tolerance Test .............................................................................. 21 
 

Biospecimen Processing and Shipping ....................................................................... 21 
 

Quality Assurance and Quality Control ...................................................................... 21 
 

Post-MEC Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 
 

Allergen Dust Collection.................................................................................. 22 
 

Dietary Interview Follow-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 
 

Flexible Consumer Behavior Survey ........................................................................ 22 
 

Food Frequency Questionnaire ............................................................................. 22 
 

Hepatitis C Follow-up .................................................................................... 22 
 

Home Urine Collection ................................................................................... 22 
 

Parent Interview of Computerized Diagnostic Interview Schedule for Children ...................................... 22 
 

iii
Physical Activity Monitor ................................................................................. 22 
 

Prostate-specific Antigen.................................................................................. 22 
 

Tuberculin Skin Test Reading.............................................................................. 23 
 

Volatile Organic Compound Exposure Monitor................................................................ 23 
 

Report of Findings......................................................................................... 23 
 

Level I Finding (Emergency) ............................................................................. 23 
 

Level II Finding (Early Report) ............................................................................ 23 
 

Level III Finding (Routine)................................................................................ 23 
 

Reporting Procedures for Minors ........................................................................... 23 
 

Reporting Procedures for Sexually Transmitted Diseases and HIV ................................................ 24 
 

Data Processing and Information Technology ................................................................... 24 
 

Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 
 

Data Collection and Processing ............................................................................ 25 
 

Data Release ........................................................................................... 25 
 

Data Usability .......................................................................................... 25 
 

Conclusion ............................................................................................... 25 
 

References ............................................................................................... 25 
 

Appendix. Glossary ........................................................................................ 27 
 

Text Figure

Floor plan of a mobile examination center used in the National Health and Nutrition Examination Survey, 2010 ....... 8 
 

Text Tables

A.	 National Health Examination Surveys, 1959–1970.......................................................... 2 
 

B.	 Periodic and population-specific National Health and Nutrition Examination Surveys, 1971–1994 ................... 2 
 

C.	 National Health and Nutrition Examination Survey, 1999–2010 ............................................... 3 
 

D.	 Protocols: National Health and Nutrition Examination Survey, 1999–2010 ...................................... 5 
 

E.	 Summary of National Health and Nutrition Examination Survey forms used to complete consent process............. 5 
 

F.	 Remuneration amount per participant: National Health and Nutrition Examination Survey, 1999–2010 ............... 9 
 

G.	 Transportation allowance: National Health and Nutrition Examination Survey, 1999–2010 ........................ 10 
 

H.	 Household interview: National Health and Nutrition Examination Survey, 1999–2010 ............................ 12 
 

J.	 Physical examination components at mobile examination center: National Health and Nutrition Examination Survey,
 

1999–2010......................................................................................... 14 
 

K.	 Oral health: National Health and Nutrition Examination Survey, 1999–2010.................................... 15 
 

L.	 Mobile examination center interviews: National Health and Nutrition Examination Survey, 1999–2010 .............. 17 
 

M.	 Laboratory tests: National Health and Nutrition Examination Survey, 1999–2010................................ 18 
 

N.	 Post-MEC examinations: National Health and Nutrition Examination Survey, 1999–2010 ......................... 22 
 

iv
Acknowledgments
 

Planning and implementing the

National Health and Nutrition

Examination Survey (NHANES)

1999–2010 involved numerous persons

and organizations. To all who deserve

mention in this report, the Centers for

Disease Control and Prevention’s

National Center for Health Statistics,

Division of Health and Nutrition

Examination Surveys (DHANES), says,

‘‘Thank you.’’ Without your diligent

efforts, the national resource represented

by NHANES data would be

significantly diminished in scope and

quality.

NHANES collaborated with a

number of federal agencies. Without

their partnership, the survey could not

have been completed. NHANES

appreciates their support in the form of

funding, staffing, and consultation. The

following government organizations

deserve mention.

Organizations within the U.S.

Department of Health and Human

Services:

+	 Centers for Disease Control and

Prevention:

‰	 National Center on Birth Defects

and Developmental Disabilities

‰	 National Center for Chronic

Disease Prevention and Health

Promotion

‰	 National Center for
 

Environmental Health
 

‰	 National Center for HIV/AIDS,

Viral Hepatitis, STD, and TB

Prevention

‰	 National Center for

Immunization and Respiratory

Diseases

‰	 National Institute for

Occupational Safety and Health

+	 Food and Drug Administration:

‰	 Center for Food Safety and

Applied Nutrition

+	 National Institutes of Health:

‰ National Cancer Institute

‰ National Eye Institute

‰ National Heart, Lung, and Blood

Institute

‰ National Institute on Aging

‰ National Institute of Arthritis and

Musculoskeletal and Skin

Diseases

‰ National Institute of Child Health

and Human Development

‰	 National Institute on Deafness

and Other Communication

Disorders

‰	 National Institute of Dental and

Craniofacial Research

‰	 National Institute of Diabetes

and Digestive and Kidney

Diseases

‰	 National Institute of

Environmental Health Sciences

‰ National Institute of Mental

Health

‰ Office of Behavioral and Social

Sciences Research

‰ Office of Dietary Supplements

+	 Office of the Assistant Secretary for

Planning and Evaluation

+ Office on Women’s Health

Other federal organizations:

+	 U.S. Department of Agriculture:

‰ Agricultural Research Service

‰ Economic Research Service

+	 U.S. Department of Housing and

Urban Development

+	 U.S. Environmental Protection

Agency:

‰ Office of Pesticide Programs

‰ Office of Research and

Development

DHANES also wishes to thank the

many state and local health departments

and community leaders for their

expertise in determining locations for

NHANES mobile examination centers

and providing letters of endorsement

that helped us establish credibility with

those selected for the survey. We thank

Westat, which performed the field data

collection. We thank the contract

diagnostic centers and laboratories and

their staffs for their dedication to the

project. Finally, we thank those who

took part in the survey as participants.

Their personal contribution of time and

effort will help improve the health and

nutritional status of all Americans.

v
Background

Starting in 1999, the National Health

and Nutrition Examination Survey

(NHANES) became a continuous,

ongoing annual survey of the

noninstitutionalized civilian resident

population of the United States. A

continuous survey allowed content to

change to meet emerging needs.

Objective

This report describes how NHANES

for 1999–2010 was designed and

implemented. NHANES is a national

survey designed to provide national

estimates on various health-related

topics.

Methods

The survey used in-person

face-to-face interviews and physical

examinations for data collection.

Approximately 5,000 people per year

participated in NHANES. The 5,000

people surveyed each year are

representative of the entire U.S.

population.

Keywords: survey design • mobile

examination center • field operations

• NHANES

National Health and Nutrition

Examination Survey: Plan and

Operations, 1999–2010

by George Zipf, M.S., National Center for Health Statistics; Michele

Chiappa, B.A., Harris Corporation; and Kathryn S. Porter, M.D.,

Yechiam Ostchega, Ph.D., R.N., Brenda G. Lewis, M.P.H., and

Jennifer Dostal, B.S., National Center for Health Statistics

Introduction
 

This National Health and Nutrition

Examination Survey (NHANES)

1999–2010 plan and operations report

provides detailed information on how

the Division of Health and Nutrition

Examination Surveys (DHANES),

within the Centers for Disease Control

and Prevention’s (CDC) National Center

for Health Statistics (NCHS), planned,

implemented, and conducted the

1999–2010 NHANES. Those who use

the NHANES public-release data sets

should find this report helpful in using

the data sets properly. This report is

structured by the order in which

NHANES is planned and implemented.

The first four sections describe the

survey history and planning. The

remaining sections describe the survey

operations, data collection, and

information technology. Additional

information is found in the Appendix,

which presents a glossary of terms used

in this report.

History of NHANES

The National Health Survey Act of

1956 provided for a continuing survey

and special studies ‘‘ . . . to secure

accurate and current statistical

information on the amount, distribution,

and effects of illness and disability in

the United States . . . ’’ and to provide

methods and processes to secure this

statistical information (1). In 1960, the

U.S. Department of Health and Human

Services (HHS) merged the National

Office of Vital Statistics and the

National Health Survey program to form

NCHS (Appendix). NCHS has been

located in a number of organizations

within HHS. Since 1987, NCHS has

been part of CDC (2). To achieve its

mission of providing information to

guide actions and policies that improve

health, NCHS conducts a number of

major data collection programs,

including NHANES.

NHANES is unique in that it

combines personal interviews with

standardized physical examinations and

laboratory tests. The interviews are

conducted in the home and at a mobile

examination center (MEC). The physical

examinations and laboratory tests are

conducted in the MEC. The purpose of

NHANES is to collect data about the

health, nutritional status, and health

behaviors of the noninstitutionalized

civilian resident population of the

United States. From its establishment in

1959, the survey has been conducted in

three separate eras: the National Health

Examination Survey (NHES) era

(1959–1970), the periodic and

population-specific NHANES era

(1971–1994), and the continuous

NHANES era from 1999 forward (1).

In 1959, the first National Health

Examination Survey (NHES I) was

conducted and focused on selected

chronic diseases, such as cardiovascular

disease and diabetes (3). NHES I

concluded in 1962. The second NHES

(NHES II) was conducted during

1963–1965 and focused on the growth

and development of children aged 6–11

years (4). The third NHES (NHES III)

Page 1
Page 2 [ Series 1, No. 56

Table A. National Health Examination Surveys, 1959–1970

Years Participant

Survey conducted Number of participants age (years) Focus

NHES I ................... 1959–1962	 7,710 interviewed 18–79 Chronic disease

6,672 examined

NHES II ................... 1963–1965	 7,417 interviewed1 6–11 Growth and development – children

7,119 examined

NHES III................... 1966–1970	 7,514 interviewed 12–17 Growth and development – adolescents

6,768 examined

1

Represents those children whose parents or guardians responded to a telephone call from an interviewer who collected information on the ages of all children within that household.

NOTE: NHES is National Health Examination Survey.

Table B. Periodic and population-specific National Health and Nutrition Examination Surveys, 1971–1994

Years Participant
 

Survey conducted Number of participants age Focus
 

NHANES I ............... 1971–1974	 28,043 interviewed 1–74 years Nutrition and health

20,749 examined

NHANES II............... 1976–1980	 25,286 interviewed 6 months–74 years Nutrition and health

20,322 examined

HHANES ................ 1982–1984	 13,689 interviewed 6 months–74 years Hispanic nutrition and health

11,653 examined1

NHANES III .............. 1988–1994	 33,994 interviewed 2 months and over Subpopulation nutrition and health

30,818 examined

1

Of those examined, participants’ ethnicities were 7,462 Mexican-American, 1,357 Cuban-American, and 2,834 Puerto Rican persons.

NOTES: NHANES is National Health and Nutrition Examination Survey. HHANES is Hispanic Health and Nutrition Examination Survey.

was conducted during 1966–1970 and

focused on the growth and development

of adolescents aged 12–17 (5). Because

the same basic survey design was used,

nearly one-third of the children

examined in NHES II were examined

again in NHES III as adolescents.

Table A provides further information on

NHES I, II, and III.

In 1971, a nutrition component was

added to the survey, and the survey

name changed to the National Health

and Nutrition Examination Survey. This

began the periodic and populationspecific era (1971–1994), during which

four surveys were conducted. The first

NHANES (NHANES I) was conducted

for 1971–1974 (augmented for

1974–1975 by an additional national

sample) and focused on the nutrition

and health of participants aged 1–74.

The Augmentation Survey included

adults aged 25–74 and did not

oversample any populations. For more

information on the augmentation, see

‘‘Plan and Operation of the HANES I

Augmentation Survey of Adults 25–74

Years: United States, 1974–1975’’ (6) at

http://www.cdc.gov/nchs/data/series/

sr_01/sr01_014.pdf.

The second NHANES (NHANES

II) was conducted during 1976–1980

and focused on nutrition and health, but

the age of eligible participants started at

6 months. The maximum age of

sampled participants remained 74 years.

For 1982–1984, NHANES shifted

to a population-specific survey. The

Hispanic Health and Nutrition

Examination Survey (HHANES) was

conducted on the three largest Hispanic

subgroups in the United States at the

time: Mexican-American, CubanAmerican, and Puerto Rican persons.

HHANES aimed to produce estimates of

nutrition and health status for these

subgroups. HHANES was similar in

design to NHANES II in that the ages

of sampled participants were 6 months

through 74 years.

In 1988–1994, a third NHANES

(NHANES III) was conducted in which

several population groups were

oversampled, including children aged 2

months to 5 years, persons over age 60,

Mexican-American persons, and

non-Mexican-American black persons.

Additionally, emphasis was placed on

the effect of the environment on overall

health, and, therefore, data were

collected on environmental exposures

(e.g., carbon monoxide, pesticides, and

others). Table B provides further

information on NHANES I, II, III, and

HHANES.

Starting in 1999, NHANES became

a continuous, ongoing annual survey of

the noninstitutionalized civilian resident

population of the United States.

NHANES excluded all persons in

supervised care or custody in

institutional settings, all active-duty

military personnel and active-duty

family members living overseas, and

any other U.S. citizens residing outside

of the 50 states and the District of

Columbia. Noninstitutional group

quarters were included; for more

information on group quarters, see

Appendix. A continuous survey allowed

content to change to meet emerging

needs. The goals of the continuous

NHANES were:

+	 To provide prevalence data on

selected diseases and risk factors for

the U.S. population.

+	 To monitor trends in selected

diseases, behaviors, and

environmental exposures.

+	 To explore emerging public health

needs.
+	 To maintain a national probability

sample of baseline information on

health and nutritional status.

The design of the sample changed

periodically as well. In the continuous

NHANES, the participant age range was

expanded to all ages. Data were released

to the public in 2-year cycles. The

sample size in a 12-month period was

approximately 5,000 individuals from 15

different county locations selected from

a sampling frame that included all 50

states and the District of Columbia.

Oversampled subgroups for 1999–2006

included non-Hispanic black persons,

Mexican-American persons, low-income

white persons (beginning in 2000),

adolescents aged 12–19, and persons

aged 70 and over. During 1999–2006, a

supplemental sample of pregnant women

was included. Oversampled subgroups

for 2007–2010 included all Hispanic

persons, non-Hispanic black persons,

low-income white persons, and persons

aged 80 and over. Table C provides

information on the number of

participants interviewed and examined

during the continuous NHANES. This

report hereafter addresses only the

continuous NHANES era for

1999–2010. For more information on

the history of NHANES, see ‘‘The

NHANES Story’’ at http://www.cdc.gov/

nchs/video/nhanes50th_ppf/intro/

ppf_intro.htm.

Table C. National Health and Nutrition

Examination Survey, 1999–2010

NHANES

2-year cycle Number of participants

1999–2000 ..... 9,965 interviewed

9,282 examined

2001–2002 ..... 11,039 interviewed

10,477 examined

2003–2004 ..... 10,122 interviewed

9,643 examined

2005–2006 ..... 10,348 interviewed

9,950 examined

2007–2008 ..... 10,149 interviewed

9,762 examined

2009–2010 ..... 10,537 interviewed

10,253 examined

NOTE: NHANES is National Health and Nutrition Examination

Survey.

Survey Planning and

Sample Design

A major advantage of continuous

NHANES data collection is the ability

to address emerging public health issues

and provide objective data on health

conditions for the U.S. population in a

timely manner. For 1999–2010,

NHANES content was modified

biannually as components were added,

changed, or removed. Changes were

also made to target new age groups,

modify data collection methods, and

update technologies. Prior to biannual

changes, NHANES conducted pilot tests

of new or revised survey material as

part of the ongoing data collection.

Planning Process

The NHANES program solicited

new content proposals in the mid-1990s

for the launch of the continuous survey,

and biannually after the survey began.

Broad oversight for planning and

content was provided through

consultation with stakeholders,

collaborating agencies, and other

research partners. These parties, as well

as those on an NHANES mailing list,

were informed every 2 years of

deadlines and guidelines for proposals

for the upcoming 2-year survey cycle.

This information was also posted on the

NHANES website. The research

proposal solicitation process required

that all persons interested in adding

content to NHANES submit a letter of

intent and a full proposal.

Letters of intent were reviewed by

the DHANES Planning Branch to

determine if the proposed content was

safe, feasible, and of sufficient public

health significance to include in

NHANES. If the letter of intent was

acceptable, the proposer was asked to

submit a full research proposal. A full

proposal included details about the

public health significance and data

collection methodology. Proposals were

evaluated based on public health

significance; appropriateness and

feasibility given the NHANES design

and sample; ethical issues; participant

Series 1, No. 56 [ Page 3

burden; and financial considerations. If

accepted, the protocol was fully

developed and prepared for field-testing

prior to use in NHANES. If required,

cognitive testing and translation

activities were completed prior to field

implementation. Similarly, laboratory

methods were tested and deemed

reliable and valid prior to their inclusion

in NHANES. Accepted proposals for

new content and content modifications

were summarized in an information

clearance request (ICR) submitted to the

Office of Management and Budget

(OMB). An ICR was submitted to OMB

every 2 years or when amendments

were necessary. OMB approved and

provided clearance for NHANES to

begin data collection. All protocols were

also reviewed and approved by the

NCHS Research Ethics Review Board

(ERB) prior to implementation in

NHANES; for more information on

ERB, see the ‘‘Ethical, Privacy, and

Confidentiality Considerations’’ section.

Sample Design

NHANES was designed to assess

the health and nutritional status of the

civilian noninstitutionalized U.S.

population. NHANES data were not

obtained using a simple random sample.

Rather, a complex, multistage

probability sampling design was used to

select a sample representative of the

civilian noninstitutionalized household

population of the United States.

Sample selection for NHANES

followed these stages, in order:

1.	 Selection of primary sampling units

(PSUs), which are counties or small

groups of contiguous counties.

2.	 Selection of segments within PSUs

that constitute a block or group of

blocks containing a cluster of

households.

3.	 Selection of specific households

within segments.

4.	 Selection of individuals within a

household; see the ‘‘Household

Interview’’ section for more

information on sample person

selection.

About 12,000 persons per 2-year

cycle were asked to participate in
Page 4 [ Series 1, No. 56

NHANES. Response rates varied by

year, but an average of 10,500 persons

out of the initial 12,000 agreed to

complete a household interview. Of

these, about 10,000 then participated in

data collection at the MEC. These

persons are located in counties across

the country. About 30 selected counties

were visited during a 2-year survey

cycle out of approximately 3,000

counties in the United States. Each of

the four regions of the United States and

metropolitan and nonmetropolitan areas

are represented each year.

Demographic Domains and

Oversampling

For certain subgroups of particular

public health interest, the proportion of

individuals in the NHANES sample was

larger than the corresponding proportion

in the U.S. population. This

oversampling increased the reliability

and precision of estimates of health

status indicators for these population

subgroups. Weighting schemes allowed

estimates from these subgroups to be

combined to obtain a national estimate

that reflected the relative proportions of

these groups in the population as a

whole. Oversampled subgroups in the

survey were:

For 1999–2006:

+	 Non-Hispanic black persons

+	 Mexican-American persons

+	 Low-income white persons

(beginning in 2000)

+	 Persons aged 70 and over

+	 Adolescents aged 12–19

For 2007–2010:

+	 Non-Hispanic black persons

+	 Hispanic persons

+	 Low-income white persons

+	 Persons aged 80 and over

During 1999–2006, a supplemental

sample of pregnant women was also

included.

Sample Weights

The weighting of sample data

permitted analysts to produce estimates

of statistics they would have obtained if

the entire sampling frame had been

surveyed. A sample weight was assigned

to each sample person. Sample weights

were considered measures of the number

of people represented by the particular

sample person. When a sample was

weighted in NHANES, it was

representative of the U.S. civilian

noninstitutionalized population.

Weighting took into account several

features of the survey: the differential

probabilities of selection for the

individual domains; nonresponse to

survey instruments; and differences

between the final sample and the total

population. Weights were adjusted for

nonresponse to the in-home interview

when creating the interview weights,

and further adjusted for nonresponse to

the MEC examination when creating the

examination weights.

Each single year and any

combination of consecutive years

comprised a nationally representative

sample of the population. However,

because NHANES went to only a small

number of PSUs each year, estimates for

single-year data were relatively unstable

(large variance estimates). In addition,

releasing only 1 year of data increased

the possibility of disclosure of a sample

person’s identity. As a result, data were

publicly released in 2-year cycles. In

general, any 2-year data cycle in

NHANES can be combined with

adjacent 2-year data cycles to create

analytic data files based on 4 or more

years of data, to produce estimates with

greater precision and smaller sampling

error. For further details on the

NHANES sample design, see the

National Health and Nutrition

Examination Survey reports on sample

design for 1999–2006 (7) and

2007–2010 (8).

Ethical, Privacy, and

Confidentiality

Considerations

The NHANES protocol was

developed and reviewed to be in

compliance with the HHS Policy for

Protection of Human Research Subjects

(45 CFR part 46), available from

http://www.hhs.gov/ohrp/humansubjects/

guidance/45cfr46.html. It was approved

by the NCHS Research ERB and

underwent annual review. Three federal

laws protected all data:

+	 Privacy Act of 1974 (5 U.S.C. 552a)

+	 Section 308(d) of the Public Health

Service Act (42 U.S.C. 242m)

+	 Confidential Information Protection

and Statistical Efficiency Act

(CIPSEA) (PL107–347)

The Public Health Service Act stipulates

that ‘‘ . . . no information may be used

for any purpose other than the purpose

for which it was supplied unless . . . [a]

person consented to its use for such

other purpose, and further that it cannot

be released or published in a form that

the particular . . . person supplying the

information or described in it is

identifiable unless such . . . person has

consented . . . ’’ (9). These strict

prohibitions, forbidding even

unintentional unauthorized disclosures,

guided the behavior of all NCHS staff

and all contractor staff.

To prevent disclosing information to

unauthorized persons, all government and

contractor staff working on NHANES read

and signed a nondisclosure affidavit, and

viewed the ‘‘NCHS Confidentiality

Practices for Federal Employees and

Contractors’’ video. Each person working

on the study was aware of his or her

responsibility to safeguard the rights of all

NHANES participants. Employees were

instructed never to divulge names or any

other information about sample participants

(those sample persons who take part in the

survey). They refrained from any

discussions about sample participants,

inside or outside of the MEC, which could

be overheard by people not on the

NHANES staff. Information kept on

interviewer tablets and MEC computers

was secured through password protection,

encryption, and other information

technology (IT) security processes; for

more information about data protection and

IT, see the ‘‘Data Processing and

Information Technology’’ section.

Ethics Review Board

The NCHS Research ERB protects

the rights and welfare of people enrolled
Series 1, No. 56 [ Page 5

in NHANES. In accordance with federal

regulations (45 CFR 46.111), ERB

reviewed and approved NHANES

protocols, including ongoing changes to

the protocol through the amendment

process. This process ensured the ethical

treatment of participants, including

vulnerable populations (e.g., children,

pregnant women, and the elderly). For

survey years 1999–2010, ERB reviewed

and approved the NHANES protocol

annually. Table D provides information

on the protocol numbers.

Informed Consent

Sample persons were informed of

the survey process and their rights as a

participant by interviewers and by

written materials, such as brochures and

flyers. After the sample person

understood the entire NHANES process,

he or she had the opportunity to consent

or assent to participate. Participation

was voluntary. Documented signed

consent was obtained from sample

persons who had reached the age of

maturity in their state (usually age 18

and over). A parent or guardian gave

permission for minors to participate. In

addition, children aged 7–17 provided

documented assent prior to participating.

An emancipated minor did not need

parental permission. For cognitively

impaired persons, consent was obtained

from guardians, parents, or

representatives who had the legal right

to consent to medical care on behalf of

the impaired person.

NHANES participation has two

phases: the home interview and the

health examination. Signed informed

consent was obtained from every sample

person for both phases during the home

interview. Interpreters were hired as

necessary to help sample persons who

did not speak or read English or

Spanish.

The consent forms were presented

to the sample person in a specific order

to ensure all necessary signatures were

captured (Table E). The consents are

described in detail below; for more

information on consents, see the

NHANES website at http://www.cdc.

gov/nchs/nhanes/nhanes2009-2010/

current_nhanes_09_10.htm.

Home interview consent form

Sample persons aged 12 and over,

and parents or guardians of sample

participants aged 18 and under, read and

signed the Home Interview Consent

form. If a sample person was unable to

read the form, the interviewer read the

entire document to the sample person in

front of a witness; then the sample

person signed the form and completed

the in-home personal interview. If the

Table D. Protocols: National Health and Nutrition Examination Survey, 1999–2010

NCHS Ethics Review

Survey and years conducted Board protocol number

NHANES 2005–2010 .................... #2005–2006
 

NHANES 1999–2004 .................... #98–12
 

sample person was unable to sign the

form, a witness signed the form to

indicate that the sample person gave

informed consent.

Examination consent brochure

and form

An examination consent form was

signed by sample persons aged 18 and

over. This consent was also signed by

sample persons aged 12 and over, and

by parents or guardians of sample

persons aged 18 and under. Sample

persons (or guardian) aged 7–11 signed

separate forms; see the ‘‘Child

examination assent brochure and form’’

section.

Before scheduling an appointment

in the MEC, the interviewer provided

the examination consent brochure and

form, a health measurements list, and

the consent form to the sample person.

The ‘‘Examination Consent Brochure’’

addressed the general procedures of the

examination components and goals of

the survey, discussed data uses and

confidentiality, and explained the

voluntary nature of participation and the

rights of sample persons. The health

measurements list showed the

components of the examination,

including laboratory assessments. As

with the Home Interview Consent form,

this material was introduced and

provided to the sample person so he or

she could read the information, ask

questions, and sign the consent form.

The sample person was given the

examination brochure and a copy of the

signed consent form to keep.

NOTES: NHANES is National Health and Nutrition Examination Survey. NCHS is National Center for Health Statistics.

Table E. Summary of National Health and Nutrition Examination Survey forms used to complete consent process

Non-DNA specimen DNA specimen

Sample participant Home Examination Examination storage consent storage consent

ages interview consent consent or assent child assent or assent or assent

0–11 months ..... Signed by parent Signed by parent . . . . . . . . .

1–6 years ....... Signed by parent Signed by parent . . . Signed by parent . . .

7–11 years ...... Signed by parent Signed by parent Signed by participant Signed by parent ...

and participant

12–17 years...... Signed by parent and Signed by parent and . . . Signed by parent ...

participant (ages 16 participant and participant

and 17 only)

18 years and over . . Signed by participant Signed by participant . . . Signed by participant Signed by participant

. . . Category not applicable.
Page 6 [ Series 1, No. 56

Child examination assent

brochure and form

In addition to parents’ or guardians’

signatures on the examination consent

form, minors aged 7–11 agreed to

participate in the examination. An assent

brochure, which was specifically

designed to explain participation to the

child and written at a fourth-grade

reading level, was presented or read

aloud. Questions were answered, and

then the child assented by signing his or

her own name. The minor was given the

brochure and a copy of the signature

form to keep.

Consents for specimen storage

NHANES sample persons were

asked to consent to have their blood,

urine, and saliva specimens stored for

future studies. The specimen consent

form highlighted the need for stored

specimens to help find new ways to

prevent, treat, and cure many diseases.

The form was designed to answer

commonly asked questions posed by

sample participants. In 2007, the form

was split into two separate specimen

storage consents: one for future genetic

studies, and one for future nongenetic

studies.

The ‘‘Consent/Assent and Parental

Permission for Specimen Storage and

Continuing Studies’’ form was used for

sample persons aged 7 and over. The

sample person was instructed to read the

consent, mark a checkbox if he or she

also consented to having his or her

blood and urine kept for future health

studies, and sign the consent. The parent

or guardian of a child under age 18 also

signed to provide parental permission

for specimen storage. The ‘‘Consent and

Parental Permission for Specimen

Storage and Continuing Studies Using

DNA’’ form was used for sample

persons aged 20 and over. The sample

person was instructed to read the

consent, mark a checkbox if he or she

consented to have his or her blood kept

for future studies that utilized genes to

understand genetic links to medical

conditions, and sign the consent.

Field Operations
 

NHANES was operationally

designed to achieve high response rates

and high-quality data. Field operations

activities included creating schedules for

site locations, making arrangements to

prepare for the arrival of MECs, staffing

and training, opening the field office,

setting up the MEC, creating an

appointment schedule for the MEC,

opening the MEC, and closing the

MEC. This section provides detailed

information on NHANES field

operations.

Schedules

Scheduling site locations was a

complex task that included multiple

considerations. Developing the survey

operations schedule involved the

sequencing of the annual PSUs (also

referred to as site locations) and

determining the dates during which

individual PSUs would open and close.

In any annual NHANES cycle, 15 PSUs

or site locations were selected prior to

beginning field operations. The calendar

dates for work in the PSUs were

determined by several factors:

+	 Location of the last site in the

previous year

+	 Distance between site locations

+	 Seasonal weather patterns

+	 Expected number of sample

participants in the site location

+	 Expected number of households to

be screened (Appendix) in the site

location

+	 Other factors specific to sites, such

as difficulties with MEC transit

After the PSU order was determined, a

detailed individualized schedule for each

site location was developed. This

schedule included dates for travel,

opening the field office and MEC,

conducting interviews and examinations,

and closing the field office and MEC.

Each site location was open for

approximately 9 weeks.

Advance Arrangements

Advance arrangements were made

to prepare for the arrival of the survey.

Activities included notifying the

community, obtaining MEC site

locations, and performing media

outreach.

Community notification

Based on U.S. Census Bureau data,

a demographic profile of each site

location was created. Listing information

was assessed, and NHANES staff

identified all county officials at a site

location who needed to be notified of

the arrival of NHANES. After an initial

in-person meeting with the local public

health director, a notification letter was

sent to county health officials, the area

agency on aging, local law enforcement,

county executives, mayors, fire

departments, and school superintendents

to inform them of the arrival of

NHANES. The letter included the

expected number of participants to be

examined and offered contact

information for any questions. County

health officials, the area agency on

aging, mayors, and others were asked to

provide endorsements of NHANES to

be used by interviewers, if needed. The

health department was also asked to

provide a list of medical and dental

clinics for possible referrals.

Location for MEC

Selecting a location for the MEC

was a critical part of the survey because

the location could greatly affect the

survey response rate. A location that was

familiar to residents with easy access

from the sampled segments was ideal.

Plumbing, electrical, sewer, and

telecommunications hookup capability

also were required.

Media outreach

Prior to household interviewing at a

site location, NHANES compiled a list

of local newspapers and media outlets.

A press kit, which included the press

release, the NHANES overview

brochure, and other NHANES materials,

was sent to these media outlets and

newspapers. The goal was for an article

about NHANES to be published in one

or more local newspapers before data

collection began. In addition, an open

house was held during the morning of
Series 1, No. 56 [ Page 7

‘‘dry run’’ day; see the ‘‘Setup and dry

run’’ section. All local media were

invited.

Staffing and Training

Staff were selected based on

previous experience, academic training,

knowledge, skills, and abilities. Many

positions required that the staff speak

both English and Spanish. Bilingual

staff were hired to address the language

needs of Spanish-speaking sample

participants. Verbal scripts in the MEC

were translated into Spanish to assist

examiners and interpreters in explaining

testing procedures and to ensure a

standardized protocol. Interpreters were

hired to assist interviewers and

examiners when necessary for any

language. Sample participants who did

not speak Spanish or English were

excluded from examination components

that contain sensitive information, such

as the MEC interview and sexually

transmitted disease (STD) testing.

A background check and a security

clearance were completed upon hiring

each staff member. Field office staff

(Appendix), including the interviewers,

and MEC staff traveled with the survey

and worked 48 weeks of the year. The

field office staff consisted of a study

manager, field manager, office manager,

and assistant office manager at each

field office. The MEC staff comprised

two examination teams. Each team

included the following staff:

+	 A MEC manager who supervised the

examination staff and oversaw

examination flow.

+	 A coordinator who directed sample

participants through the MEC,

managed appointments, and verified

completion of MEC examinations.

+	 A physician who conducted medical

examinations, evaluated for referrals,

and served as a safety officer.

+	 Two health interviewers who

administered questionnaires for

physical and mental health.

+	 Two dietary interviewers who

administered the 24-hour dietary

recall.

+	 Four health technologists who

collected medical examination data

such as body measurements, vision

tests, respiratory health

examinations, bone density scans,

hearing tests, and glucose solution

for the glucose tolerance test.

+	 Three medical technologists who

processed biological specimens,

conducted the complete blood count

and pregnancy tests, and prepared

specimens for shipment to

laboratories across the United States.

+	 A phlebotomist, who conducted the

phlebotomy interview, administered

the fasting questionnaire, drew blood

for laboratory tests, administered the

glucose solution, and served as a

backup examiner for other

components.

In addition to those listed, a dental

hygienist performed the oral health

component for 2009–2010. A dentist (or

dental examination team made up of a

dentist and an oral health recorder)

performed the oral health component for

1999–2004. Health technologists were

used in the interim.

Annual retraining was conducted for

all staff (field office, interviewer, and

MEC) to make certain that they were

updated on changes to components and

protocols and procedures, and that they

were introduced to new content.

Information on initial training for the

MEC staff and field office staff follows.

Field office staff training

The field office staff attended a

10-day interviewer-training course so

that they were proficient in the

mechanics of sample participant

recruitment and household interviewing.

The field office staff spent 4 to 5 days

learning general field-office procedures

and specific details about their roles.

The training also educated the staff on

how to perform manual opening and

closing of site locations, manage case

workflow using an automated system,

monitor site production using daily

reports, and comply with procedures for

handling sample participant queries,

documentation, and refusals.

Interviewer training

Training was designed to make new

interviewers proficient at making contact

with residents of sampled households,

using screening techniques properly, and

obtaining consent to participate from

selected individuals. The interviewer

training program consisted of a 10-day

course and covered:

+	 The purpose and goals of NHANES

and how to properly encourage

participation.

+	 The adherence to confidentiality and

high performance standards required

for data collection.

+	 The administration and navigation of

the interview, which includes three

computerized household

questionnaires.

+	 The case workflow and appropriate

use of survey materials.

+	 The administrative procedures for

personnel working in the field

environment.

New interviewers shadowed seasoned

interviewers for a period of time prior to

interviewing on their own.

MEC staff training

The MEC staff was trained

according to their specific jobs. Each

examination component in the MEC

involved multiple roles and

responsibilities; therefore, each MEC

staff member was trained by a subject

matter expert. MEC staff training was

rigorous and done through procedure

demonstrations and practice. Training

included:

+	 Learning about the objectives and

goals of the examination component.

+	 Demonstrations of protocols and

procedures.

+	 Practicing the procedures.

+	 Learning about quality control and

quality assurance.

+	 Learning how to maintain and

perform calibrations on the

equipment.

+	 Learning the MEC opening and

closing protocols.

+	 Learning to maintain the inventory

for supplies.

Site visits by DHANES staff were done

throughout the year to observe MEC

staff as part of quality assurance.
Page 8 [ Series 1, No. 56

Opening the Field Office

The NHANES field office was

located in the PSU. The field office

supported activities regarding household

interviewing and MEC data collection.

Activities included coordinating

procedures (e.g., monitoring site

production), managing household case

assignments and refusal conversion

efforts, scheduling examination

appointments, and handling staffing

issues.

Opening the field office required

hiring a local receptionist; preparing

case assignments for field interviews;

preparing a map and directions to the

MEC for sample participants; receiving

survey supplies; setting up computer

equipment, telephones, and common

areas; and becoming familiar with the

sample area (Appendix). The field office

opened 1 week before interviewing

began and remained open until the MEC

examinations ended.

Mobile Examination

Center

Trailer design

NHANES was designed to collect

data by direct physical examinations,

clinical laboratory tests, and related

measurement procedures. Data were

collected in a standardized environment

to minimize site-specific error. Each

MEC was a group of four trailers set up

side by side and connected by enclosed

passageways (Figure). NHANES

1999–2010 included three MECs, two of

which were actively used for data

collection while the third traveled to a

new location. The layout was identical

in all three MECs to avoid bias in data

collection between MECs. A MEC tour

is available at http://www.cdc.gov/nchs/

nhanes/mec_tour/mectour.htm.

All supplies, tools, and materials

introduced to the MEC environment

were evaluated before they were used.

Each MEC had a reception area, nine

examination rooms, four interview

rooms, a laboratory, three restrooms, and

a staff lounge. Specific customizations

(e.g., a soundproof booth for
 

audiometry) were featured in each MEC.
 

Examination rooms

The nine MEC examination rooms

varied in size depending on the

requirements of the component. For

example, a larger room was designated

for the dual-energy X-ray

absorptiometry, or DXA, instrument.

MEC rooms were modified as necessary

to accommodate new components.

Safety and special

accommodations

The safety of the MEC staff and

sample participants was an NHANES

priority. Special accommodations in the

MEC included a handicapped restroom

with handrails, a hydraulic wheelchair

lift, and a baby changing table. The

MEC was a nonsmoking facility. Fire

extinguishers were placed throughout

Body 

measurement Reception 

Doctor Dietary 

interviews 

Interview 

rooms 

Blood 

pressure 

study 

Mobile examination center (MEC) diagram 

Breathing 

test 

Home 

urine 

collection 

Hearing 

test 

Bone 

density 

Dental 

screening 

Laboratory Staff area 

Blood draw Passageway Passageway 

SOURCE: CDC/NCHS, National Health and Nutrition Examination Survey, MEC 2010. 

Figure. Floor plan of a mobile examination center used in the National Health and Nutrition

Examination Survey, 2010

the MEC, and exit doors were

highlighted in every trailer. The

following was kept in the physician’s

examination room for emergency

response:

+ Emergency medical kit

+ Automated external defibrillator

+ Two portable oxygen tanks

+ Portable blood pressure equipment

Pocket masks for cardiopulmonary

resuscitation, or CPR, were located

throughout the MEC, and examination

staff maintained current certification in

the American Heart Association’s Basic

Life Support for Healthcare Providers.

Mock emergency drills were held

periodically in the MEC to permit

practice of the emergency procedures.

Telephone numbers for local fire and

rescue squads were posted in the MEC,

and ‘‘911’’ was used to initiate the local

emergency response system.
Series 1, No. 56 [ Page 9

Setup and dry run

Prior to conducting examinations in

the MEC, the trailers were set up with

the proper equipment and supplies

needed for each component. Once the

MEC was set up, the equipment was

calibrated and tested to ensure proper

functioning. NHANES held a ‘‘dry-run’’

day to test the equipment. The dry run

usually occurred the day before

examinations began and allowed for

practice examination sessions to be

administered for each component using

volunteer examinees. In addition, blood

and urine were collected and sent to

laboratories. Randomly selected dry-run

specimens were also sent with alternate

identification numbers for blind

duplicate quality control.

Appointment schedule

An appointment for an examination

in the MEC was scheduled for each

sample participant when the interviewer

was in the participant’s home. That

interviewer called the field office to set

up the appointment. Each sample

participant was randomly assigned a

morning appointment or an afternoon or

evening appointment. If a sample

participant was unable to attend his or

her assigned session, he or she made an

alternative appointment. An individual

examination could last between 40

minutes and 4 hours, depending on the

age and gender of the sample

participant.

Each examination session was 4 hours

and could include 10–12 sample

participants. If a sample participant was

assigned to a morning appointment, he or

she was asked to fast prior to the

appointment were reviewed. If the

participant did not have a telephone, the

interviewer visited the home to provide an

in-person reminder.

Opening and closing

Once examinations began, the MEC

was open 5 days a week and operated

on a rotating schedule to allow sample

participants to choose from a variety of

appointments. The MEC was closed 2

days a week, and these days changed

from week to week. The MEC typically

remained open for 6 weeks. Once

examinations were concluded in a

specific location, the MEC closed and

went through ‘‘teardown.’’ This involved

checking the inventory, repacking

supplies, securing equipment, and

preparing for travel. The MEC then

traveled to the next assigned location.

Remuneration

NHANES had other approaches for

gaining participation, which included

remuneration and a transportation

allowance. NHANES materials were

available in both English and Spanish.

Sample participants were remunerated at

the conclusion of their examination

appointment. The amount of the

remuneration depended on the sample

participant’s age and the session

attended. Table F shows the

remuneration amounts by survey year,

participant circumstance, and session.

Each sample participant’s session

was randomly assigned for morning,

afternoon, or evening, as stated above.

Sample participants were fully

compensated for coming to their

assigned session, but were not fully

compensated if they attended a

nonassigned session. Remuneration was

also given to a parent or guardian if his

or her child was selected to participate

but he or she was not.

Sample participants also received a

transportation allowance for driving to

the MEC. If a sample participant did not

drive, a taxi was provided at no cost.

Table G has information on the

transportation allowance provided based

on survey year, mileage to the MEC

location, and whether the location was

urban or rural. For information on

additional remuneration for other

components, see the ‘‘Post-MEC Data

Collection’’ section.

Household Interview

The NHANES household interview

consisted of four parts: screener

questionnaire, relationship questionnaire,

sample participant questionnaire, and

family questionnaire. Trained household

interviewers administered the

questionnaires in the sample

participant’s home. In very rare

instances, the household interview took

place outside of the home (i.e., in the

field office or a public location). The

interview was conducted using a

computer-assisted personal interview

system and Blaise software. Interpreters

Table F. Remuneration amount per participant: National Health and Nutrition Examination

Survey, 1999–2010

appointment. The average time between Attending assigned Attending alternative

Survey years Participant circumstance session session interview and examination was 2 weeks. A

reminder letter was mailed to the

participant 1 week before the scheduled

exam. The reminder letter included the date

and time of the appointment, transportation

information, directions to the MEC,

appropriate fasting instructions, and the

remuneration (cash payment) amount.

Forty-eight hours before a MEC

examination appointment, the field office

staff called the participant to remind him or

her of the upcoming appointment.

Instructions related to the MEC

1999–2000........ 
 

2001–2004........ 
 

2005–2008........ 
 

2009–2010........ 
 

Aged 12 and over $70 $40
 

Person with diabetes on insulin 40 40
 

Under age 12 30 30
 

Aged 16 and over 100 70

Person with diabetes on insulin 70 70

Aged 12–15 50 30

Under age 12 30 30

Aged 16 and over 100 70

Aged 12–15 50 30

Under age 12 30 30

Aged 16 and over 125 90

Aged 12–15 90 40

Under age 12 40 40
Page 10 [ Series 1, No. 56

Table G. Transportation allowance: National Health and Nutrition Examination Survey, emancipated minor (criteria determined by 1999–2010 state law).

Survey years	 Mileage to MEC1 location Urban Rural

1999–2006.................... Less than 16 miles

16–30 miles

31–59 miles

More than 60 miles

$25

35

45

55

$20

30

40

50

2007–2010.................... Less than 16 miles

16–30 miles

31–59 miles

More than 60 miles

30

45

55

70

25

40

50

65

1

Mobile examination center.

for the household interviews were used

for non-English/non-Spanish

participants. Table H provides details on

each section of the household interview.

Specific household interview questions

may have changed during the 2-year

survey cycles, but the most recent major

topics are included in Table H; see

respective data documentation available

from the NHANES website: http://

www.cdc.gov/nchs/nhanes/nhanes_

questionnaires.htm. Some household

interview sections were related to

examination components, laboratory

tests, or the MEC interview; see the

NHANES Survey Content Brochure at

http://www.cdc.gov/nchs/data/nhanes/

survey_content_99_12.pdf for more

information.

Screener

Prior to screening, households were

sent a letter introducing NHANES and

providing information that the household

address had been selected as part of the

NHANES sample. Each screener case

assignment consisted of a sampled

household address and a randomly

assigned, computer-generated message

explaining what sex, age, and race or

ethnicity was necessary for the specific

address. The field interviewer did not

know in advance if anyone in the

household would be selected to be a

participant. In most cases, the screener

was conducted on the doorstep.

The field interviewer arrived at the

home, showed an official identification

badge, and briefly explained the

survey’s purpose. As a reminder, the

field interviewer showed the notification

letter stating that the household address

was part of the NHANES sample. The

field interviewer conducted the screener

questionnaire to enumerate the

household and to determine eligibility to

participate further in NHANES. The

screener gathered information regarding

each resident’s age, gender, race and

ethnicity, and income. Based on the

questionnaire information collected, a

computer algorithm randomly selected

one, some, all, or none of the household

residents to participate. If no one from

the house was selected, it was because

no household member met the criteria

selected by the algorithm. If eligible

individuals were identified, the

interviewer proceeded with the

relationship questionnaire.

Certain circumstances prevented an

interviewer from completing a screener

questionnaire, such as:

+	 A vacant unit or residence.

+	 An address not qualifying as a

dwelling unit.

+	 A nonexistent sampled dwelling

unit.

+	 A household resident refusing

participation.

Relationship Questionnaire

If at least one household member was

eligible to participate, the relationship

questionnaire was administered after the

screener. The intent of the relationship

questionnaire was to divide all household

residents into individual family units, to

determine how many family units were in

each household. The U.S. Census Bureau’s

Current Population Survey (CPS) family

definitions were used, to ensure that the

appropriate number of family

questionnaires was created by the software

administered by the field interviewer. All

eligible screener and relationship

questionnaire respondents were adult

household members at least age 18 or an

Sample Person

Questionnaire

Prior to conducting the sample

participant or family questionnaires,

sample participants (aged 18 and over)

were asked to sign a home interview

consent form, agreeing to participate in

the household interview portion of the

survey; see the ‘‘Ethical, Privacy, and

Confidentiality Considerations’’ section

for informed consent procedures.

Sample participants aged 16 and 17

were asked to sign a document of

assent. Parents or guardians of

participants under age 18 gave parental

permission. Eligible sample participants

within a household were asked to

complete the sample participant

questionnaire. Field interviewers

were trained to conduct the sample

participant questionnaire prior to the

family questionnaire, because the family

questionnaire has content that is more

sensitive. The sample participant

questionnaire collected information on

the sample participant’s demographic,

socioeconomic, dietary, and healthrelated history. The sample participant

questionnaire was administered to all

eligible participants or their proxies;

however, each questionnaire section

administered depended on the sample

participant’s age (Table H).

Family Questionnaire

The family questionnaire was

completed for every family unit (e.g., a

married couple, a couple living as

married, and others) sampled within the

household. CPS family definitions were

used. More than one ‘‘family’’ applied

to households where unrelated persons

were residing (e.g., roommates, lodgers,

guests without permanent housing, and

others). The family questionnaire asked

questions about each sample participant

as well as the nonsampled head of the

family. The questionnaire included

sections related to education level,

ethnicity, occupation, health insurance

coverage, and family income.

Information on general household
Series 1, No. 56 [ Page 11

characteristics was also collected. For

more information on the screener,

relationship questionnaire, sample

participant questionnaire, and family

questionnaire, see the NHANES website

at http://www.cdc.gov/nchs/nhanes/

nhanes2009-2010/questexam09_10.htm.

Household Water

Collection Component

At the conclusion of the household

interview, the field interviewer collected

a water sample in households with a

sample participant aged 12 or over. The

water collection component consisted of

the field interviewer collecting a single

tap water sample from the bathtub the

sample participant used, or from any

nonaerated spigot. The water sample

was tested for volatile organic

compounds (VOCs) and perchlorates

only in a subsample of households. The

household water sample test results were

then linked to the appropriate sample

participants who were part of the

VOC/perchlorate water subsample; see

the ‘‘MEC Biospecimen Collection’’

section for more information on

laboratory tests on water.

MEC Examinations

and Interviews

NHANES examinations took place

in the MEC. The controlled environment

of the MEC allowed physical

measurements to be done under identical

conditions at each survey location. This

section addresses examination

components and interviews conducted in

the MEC for 1999–2010. Eligibility for

examination components was

determined by the participant’s age and

gender. Some MEC examinations are

related to a household interview section

or laboratory test. Procedures and

protocols for each component can be

found in each component’s procedures

manual on the NHANES website at

http://www.cdc.gov/nchs/nhanes/

nhanes_questionnaires.htm.

MEC Examination

Components

Table J summarizes NHANES MEC

examination components for 1999–2010.

Audiometry

The audiometry component obtained

data on hearing impairment, identified

risk factors for hearing loss, and

monitored early hearing losses

consistent with overexposure to noise.

The audiometry component consisted of

four parts: (a) a pre-examination

audiometric questionnaire, (b) a brief

otoscopic screening (physical)

examination of the ear canals and

eardrums, (c) tympanometry, and (d)

pure tone air conduction audiometry.

This component was conducted on

sample participants aged 20–69 for

1999–2004, and participants aged 12–19

and 70 and over for 2005–2010.

Anthropometry

The anthropometry component

obtained data on selected body measures

to be able to: (a) provide estimates on

the prevalence of obesity and related

measures; (b) study the association

between body measures and such health

conditions and risk factors as

cardiovascular disease, diabetes,

hypertension, and activity and dietary

patterns; and (c) monitor growth and

development in children. Thirteen body

measurements were collected on sample

participants. Age ranges varied for each

body measurement. This component was

conducted during 1999–2010.

Balance

The balance component examined

normal and abnormal balance in adults,

and the relationship between balance

disorders and other factors. The protocol

consisted of two parts: (a) a short

pre-examination screening questionnaire,

and (b) a modified Romberg Test of

Standing Balance on Firm and

Compliant Support Surfaces. The

balance component was conducted on

sample participants aged 40–69 for

1999–2000, and sample participants

aged 40 and over for 2001–2004.

Bioelectrical impedance analysis

The bioelectrical impedance

analysis, or BIA, component measured

the electrical impedance of body tissues

and assessed fluid volumes, total body

water, body cell mass, and fat-free body

mass. This component was conducted on

sample participants aged 8–49 for

1999–2004.

Blood pressure

See ‘‘Physician examination’’ in this

section.

Cardiovascular fitness

The cardiovascular (CV) fitness

component obtained data on CV fitness

to (a) provide prevalence estimates of

persons at risk due to poor physical

fitness, and (b) study the association

between CV fitness and other health

conditions and risk factors, such as

obesity, CV disease, diabetes,

hypertension, activity, and dietary

patterns. CV fitness was assessed with a

submaximal treadmill test (not a

maximal test to exhaustion) on sample

participants aged 12–49. This

component was conducted for

1999–2006.

Dermatology

The dermatology component

obtained data to assess the prevalence of

psoriasis and hand dermatitis in the

adult population. Four digital images

were taken by a health technician using

a Kodak DCS760 digital camera with a

50mm lens. The poses were: ‘‘BACK

with ELBOWS,’’ ‘‘INNER ARM,’’

‘‘FRONT OF LEGS with HANDS,’’ and

‘‘BACK OF LEGS with PALMS.’’ The

dermatology component was conducted

on sample participants aged 20–59

during 2003–2004.

Dual-energy X-ray

absorptiometry

The dual-energy X-ray

absorptiometry, or DXA, component

obtained data to assess overall skeletal
nal Health and Nutrition Examination Survey, 1999–2010

Description Survey years Age (years)1

Enumeration of the household to determine eligible participants; administered at doorstep 1999–2010 18 and over

Determined relationships of household members to others in household 1999–2010 18 and over

Participant asked what language is spoken in the home 1999–2010 12 and over

Questions regarding if the air quality was bad, whether the participant did anything differently and, if so, what they did 2007–2010 16 and over

Questions regarding if diagnosed with allergies, whether had allergy attack in past year, avoided or removed pets from 2005–2006 1 and over

home because of allergies, type of allergies, age at diagnosis, and allergy symptoms (e.g., rash or sinus infection)Questions regarding pain in the back, neck, or hip area 2009–2010 20–69Questions regarding quality of hearing, whether participant ever had tubes in ears, more than three ear infections, a 1999–2010 1 and over

hearing aid or other devices, how often hearing aid was worn, whether ringing or buzzing was ever present, if bothered by

those symptoms, whether participant’s job or personal life required being around loud noises or firearms, and whether

hearing protection was used in those instances

Questions regarding dizziness, falling, treatment if any, result of treatment, and blood relatives with same condition 1999–2004 40 and over

Questions related to high blood pressure diagnosis and treatment 1999–2010 16 and over

Questions regarding chest pain, when the pain occurs, how often, whether it stops when physical activity stops, length of 1999–2010 40 and over

time it usually occurs, and whether participant also has shortness of breath or pain in arms, legs, or neckQuestions regarding any restrictions on playing sports, recommended physical activity from physician, pain during 2003–2004 12–49

physical activity, balance and dizziness problems, and problems walkingParticipants were asked if they wore reading glasses, then they were asked to manually copy symbols shown on a 1999–2002 60 and over

computer screen; no additional questions followed the exercise

Questions regarding education, marital status, military service, and other demographic 1999–2010 All ages from birth

information

Questions regarding skin and skin diseases, sun exposure, and sun protective behavior 1999–2010 20–59

Questions regarding diagnosis of diabetes, age at diagnosis, history of prediabetes, taking insulin, how much insulin, how 1999–2010 1 and over

often taken, blood tests done in the past year, how often and how much glucose is checked, and how often a doctor or

diabetes specialist is seen

Questions regarding food or drink consumed in the past month 2009–2010 2–11

Questions regarding dietary supplements, nonprescription antacids, prescription medications, and asthma medications 1999–2010 All ages from birth

Questions regarding breastfeeding and length of time; milk consumption, type, and amounts; whether participant ate

school lunches or breakfasts, was part of a government-sponsored meal program, and how often already-prepared mealswere eaten compared with homemade meals; and whether the participant had food allergies or was a vegetarian 1999–2010 All ages from birth

Questions related to location of dust collection 2001–2004 1 and over

Questions regarding birth, birthweight, and current weight 1999–2010 Birth–15Questions regarding type of insurance coverage, coverage of prescription drugs, and uninsured status during the past 12

months 2005–2010 All ages from birth

Questions regarding overall health and access to medical care 1999–2010 All ages from birth

Questions regarding history of hepatitis A, hepatitis B, and human papillomavirus vaccines and the doses received for

each 1999–2010 All ages from birth

Verification of gender, date of birth, age, and full name 1999–2006 All ages from birthQuestions regarding kidney conditions, such as kidney stones and dialysis 1999–2010 20 and overQuestions regarding the presence of different medical conditions, such as asthma and celiac disease 1999–2010 1 and over

Questions regarding pain in areas of body and length of time pain was present 1999–2004 20 and over

Questions regarding hours worked in previous week, type of work done, how long employed, and whether exposed to

fumes of any kind 1999–2010 16 and over

Page 12[ Series 1, No. 56
nal Health and Nutrition Examination Survey, 1999–2010—Con.

Description Survey years Age (years)1

Questions regarding the health of teeth and gums 1999–2010 30 and over

Questions regarding fractured bones, how fractures occurred and how many times, whether diagnosed with osteoporosis, 1999–2010 20 and over

treatments if any, and family history of fractures or osteoporosis

Questions regarding how many days a week more than 1 hour of physical activity is done, hours on the computer in the past 30

days, hours watching TV in the past 30 days, and types and frequency of physical activities 1999–2010 2 and over

Questions regarding long-term impairments, health problems, special education and assistance, work limitations, and physical andemotional limitations 1999–2010 5 and over

Questions regarding trouble breathing, persistent cough, duration of cough, phlegm, and restlessness due to cough or breathingproblems 1999–2010 1 and over

Questions regarding trouble sleeping and diagnosis of sleep disorder 2005–2010 16 and over

Questions regarding smoking in the past 5 days, type of tobacco used (e.g., cigar, cigarette, pipe, chewing, and others), how

many of those tobacco products were smoked per day, and whether participant is trying to quit 1999–2010 20 and over

Questions regarding whether participant has emotional support, who from, in need of more support, attends church, needs financial help, and has close friends available to help 1999–2008 60 and over

Questions regarding previous tuberculosis (TB) skin tests, TB symptoms, and active TB symptoms 1999–2000 1 and over

Questions regarding blindness; eyesight quality with glasses or contacts; difficulty performing regular daily activities;

history of cataracts, glaucoma, or macular degeneration; and treatments, if any 1999–2008 20 and over

Questions regarding self-perception of weight, self-reported weight over the participant’s lifetime, attempted weight loss during the

past year, and methods used to try to lose weight and to keep from gaining weight 1999–2010 16 and over

Questions regarding demographics, such as place of birth and education, and occupation 1999–2010 18 and overQuestions regarding eating habits of family and how much money is spent on food 2007–2010 18 and overQuestions regarding food eaten in the last 12 months and the reasons why certain foods were not eaten 1999–2010 18 and over

Questions regarding family and participant health coverage; kind of coverage; whether plan included dental, limited to specific

doctors or could choose, and HMO or PPO; lack of health insurance in the last year; and discontinued health

insurance and why 1999–2004 18 and over

Questions regarding how many rooms in dwelling unit, how long family has lived there, and year it was built 1999–2010 18 and over

Questions regarding family income; whether income was from a job, Social Security, retirement benefits, disabilitypension, or state assistance programs; and how much income 1999–2010 18 and over

Questions regarding products used in or outside of the home 1999–2004 18 and over

Questions regarding smoking in the household, who smokes, and how often 1999–2010 18 and over

Questions regarding the spelling of names and street addresses of two persons not related to the family 1999–2010 18 and over

-year cycle to 2-year cycle within the continuous National Health and Nutrition Examination Survey (NHANES). However, those changes are not listed here; for more information, see the NHANES website

Series 1, No. 56[ Page 13
Page 14 [ Series 1, No. 56

Table J. Physical examination components at mobile examination center: National Health and Nutrition Examination Survey, 1999–2010

Component Description Survey years

Audiometry ................. Hearing test 1999–2010

Anthropometry ............... Body measurements such as height, weight, and waist circumference 1999–2010

Balance ................... Modified Romberg test of balance 1999–2004

Bioelectrical impedance analysis .... Estimation of fluid volumes, total body water, and fat-free body mass 1999–2004

Blood pressure............... Measurement of systolic and diastolic brachial artery pressure 1999–2010

Cardiovascular fitness .......... Determination of heart rate during a submaximal treadmill test 1999–2006

Dermatology ................ Assessment for selected skin conditions from digital images of skin 2003–2004

Dual-energy X-ray absorptiometry . . . Measurement of body composition and bone density 1999–2010

Lower extremity disease ......... Determination of ankle brachial pressure index; assessment for peripheral neuropathy 1999–2004

Muscle strength .............. Strength test of knee flexion and extension; timed walk 1999–2002

Ophthalmology ............... Visual field testing; grading of digital retinal images for retinal conditions (see ‘‘Vision’’) 2005–2008

Oral health ................. Assessments of oral diseases and conditions including dental caries, periodontal 1999–2010

disease, and other conditions

Respiratory health............. Lung function testing and measurement of exhaled nitric oxide 2007–2010

Tuberculin skin test ............ Tuberculin skin test 1999–2000

Vision .................... Assessments of near and distance visual acuity (see ‘‘Ophthalmology’’) 1999–2008

changes that often occur with age. This

component measured bone mineral

content and bone mineral density. A

body composition (whole-body) scan

was conducted to determine fat mass,

lean tissue mass, bone mineral content,

and total body fat percentage. This

component was conducted on sample

participants aged 18 and over in 1999,

aged 8 and over for 2000–2004, and

aged 8–69 for 2005–2006. Scans of the

femur and anterior-posterior spine were

conducted on sample participants aged 8

and over for 2005–2010. Femur scans

provided bone measurements for the

total femur, femoral neck, trochanter,

intertrochanter, and Ward’s triangle.

Spine scans provided bone

measurements for the total spine and

vertebrae L1–L4.

Lower extremity disease

The lower extremity disease (LED)

component collected data to provide

prevalence of diagnosed and undiagnosed

LED, including those at high risk for late

complications of the disease (i.e., ulceration

and amputation). The two major

manifestations of LED are peripheral

vascular disease and peripheral neuropathy.

Peripheral vascular disease was evaluated

using the ankle brachial pressure index.

Peripheral neuropathy was assessed by a

sensory examination of the feet using a

monofilament. Both tests were conducted

on sample participants aged 40 and over.

This component was conducted for

1999–2004.

Muscle strength

The muscle strength component

(also called physical functioning)

assessed lower body strength. Isokinetic

strength of the knee extensors and

flexors was measured. The muscle

strength component was conducted on

sample participants aged 50 and over

who were also asked to do a measured

walk in addition to the isokinetic

testing. The 20-foot measured walk and

isokinetic testing were conducted during

1999–2002. The 8-foot measured walk

was conducted during 2000–2002.

Ophthalmology

The ophthalmology component

obtained data to assess the prevalence of

vision loss and retinal diseases, such as

macular degeneration. Two eye

examinations were completed for this

component: (a) a visual field test using

frequency-doubling technology, or FDT,

perimetry and (b) digital fundus

photography using an ophthalmic digital

imaging system to assess the presence

of diabetic retinopathy, age-related

macular degeneration, and other retinal

diseases (see also the following

‘‘Vision’’ section). The ophthalmology

component was conducted on sample

participants aged 40 and over for

2005–2008.

Oral health

The oral health component obtained

data to monitor oral health status, including

risk factors for disease and access to

preventive and treatment services. Many

assessments have cycled in and out since

1999. Table K shows the oral health

assessments for 1999–2010.

Peripheral neuropathy

See ‘‘Lower extremity disease’’ in

this section.

Physician examination

The physician examination consisted

of a blood pressure assessment on

participants aged 8 and over, radial pulse

rate determination on participants aged 5

and over, and apical heart rate auscultation

on infants from birth to age 4 years. The

blood pressure assessment obtained data to

assess the prevalence and trends in

hypertension, and monitored risk factors for

major cardiovascular conditions. This

component was conducted during

1999–2010.

The physician examination also

consisted of:

+	 Pretest counseling for STD testing.

+	 Providing instructions to females on

using a swab for self-collecting a

vaginal fluid specimen for selected

STD tests.

+	 Counseling participants who have

abnormal findings.

+	 Managing medical emergencies in

the MEC.

Respiratory health

The exhaled nitric oxide (ENO)

component collected data to provide a

noninvasive marker of airway
Series 1, No. 56 [ Page 15

Table K. Oral health: National Health and Nutrition Examination Survey, 1999–2010 to assess diets in the U.S. population, 2

Assessment Participants’ age (years) Survey years

Basic screening exam ................. 5 and over 2005–2008

3–19 2009–2010

Coronal caries ...................... 2 and over 1999–2004

Dental sealants...................... 2–34 1999–2004

Fluorosis. . . . . . . . . . . . . . . . . . . . . . . . . . 6–49 1999–2004

6–19 2009–2010

Functional occlusal ................... 25 and over 2003–2008

Incisal trauma. . . . . . . . . . . . . . . . . . . . . . . 10–29 1999–2004

Orofacial pain exam ................... 13–69 1999–2004

Periodontitis........................ . . . 1999–2004

Gingival bleeding ................... 12–49 1999–2000

Loss of attachment .................. 19 and over 1999–2000

13 and over 1999–2004

30 and over 2009–2010

Periodontal bleeding .................. 13 and over 2001–2004

Root caries ........................ 18 and over 1999–2004

Saliva. . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 and over 1999–2000

Tooth count ........................ 2 and over 1999–2004

5 and over 2005–2008

3–19 and 30 and over 2009–2010

Tooth wear ........................ 13 and over 2003–2004

. . . Category not applicable.

inflammation, a factor in asthma and

other possible lung diseases. Fractional

ENO was measured using a biomedical

device. ENO was performed before

spirometry because spirometric

maneuvers have been shown to reduce

exhaled nitric oxide levels. The ENO

component was conducted on sample

participants aged 6–79 for 2007–2010.

The spirometry component obtained

data on chronic obstructive pulmonary

disease, or COPD. Lung function was

tested to determine the amount and

speed of air that a person can exhale

after taking in the deepest possible

breath. The spirometry component was

conducted on sample participants aged

6–79 for 2007–2010.

Tuberculin skin test

The tuberculin (TB) skin test

component obtained data to provide

information on the extent of tuberculosis

infection in the United States. Sample

participants aged 1 and over were tested

with a TB-purified protein derivative

(PPD) product, PPD S–1, the standard

antigen. This component was conducted

for 1999–2000.

Vision

The vision component obtained data

to measure the prevalence of visual

impairment and evaluated functional

impairment related to vision. This

component consisted of three parts:

(a) determination of the prescription of a

participant’s eyeglasses, if worn; (b) a

distance visual acuity and objective

refraction/keratometric evaluation; and

(c) a vision Near Card test (see also the

preceding ‘‘Ophthalmology’’ section).

The vision component was conducted on

sample participants aged 12 and over for

1999–2008.

Interviews in the MEC

Dietary interview

The dietary interview component

obtained detailed dietary intake

information from sample participants.

Dietary intake data were used to

estimate the types and amounts of foods

and beverages consumed; to estimate

intakes of energy, nutrients, and

non-nutrient food components from

foods and beverages; and to assess

intake of water. The dietary interview

comprised three sections: (a) dietary

recall, (b) nutritional supplement and

antacid use, and (c) post-recall. This

component was conducted on sample

participants of all ages (with proxy, if

necessary) for 1999–2010. To allow for

better estimates of usual nutrient intakes

days of dietary intake data were

collected for 2002–2010.

Private health interview

The private health interview

consisted of questionnaires addressing

many health-related topics that were

sensitive and was conducted in a private

MEC interview. The interview consisted

of the computer-assisted personal

interviewing system (CAPI), the audio

computer-assisted self-interviewing

system (ACASI), and the critical data

items. Sample participants aged 8 and

over were eligible for the private

interview. This component was

conducted for 1999–2010.

Computer-assisted personal

interviewing

The first part of the private health

interview used CAPI and was conducted

by a MEC interviewer. Health-related

questions were asked based on the

sample participant’s age and gender.

Table L shows the interview sections for

the CAPI. All sections of the CAPI

could be administered using a proxy

interview or an interpreter if needed. As

part of the health-related questions, a

mental health questionnaire was

administered during 1999–2004. It was

split into three subsections: (a) the youth

Computerized Diagnostic Interview

Schedule for Children (CDISC), (b) the

parent CDISC, and (c) an NHANES

version of the World Health

Organization Composite International

Diagnostic Interview (CIDI).

The youth CDISC was administered

to sample participants aged 8–19 and

consisted of questions about panic

disorder, generalized anxiety disorder,

eating disorders, and depressive

disorders. The parent CDISC was a

follow-up and is further mentioned in

the ‘‘Post-MEC Data Collection’’

section. The CIDI was administered to

sample participants aged 20–39 and

consisted of a panic disorder,

generalized anxiety disorder, and

depressive disorder diagnostic module,

which addressed diagnoses present in

the past 12 months. No proxies were

used during the CIDI.
Page 16 [ Series 1, No. 56

Audio computer-assisted self

interviewing

The second part of the private

interview used an ACASI system.

Sample participants aged 12–69 were

given a set of headphones and asked

sensitive questions (Table L) to which

they could respond using the touch

screen. The MEC interviewer was not

present for the ACASI, and no proxies

were allowed.

Critical data items

The third part of the private

interview obtained or verified key pieces

of data about the sample participant.

Critical data items were important for

recontacting the sample participant with

information regarding his or her

examination or laboratory results.

Sample participants were verbally asked

by the MEC interviewer for the correct

or exact spelling of their name, their

date of birth, and a correct contact

telephone number. For more information

on the private interview, see the

NHANES website at http://www.cdc.

gov/nchs/nhanes/participant.htm.

MEC Biospecimen

Collection

NHANES collected biological

specimens (biospecimens) during MEC

appointments for analysis in

laboratories. This included the

collecting, processing, storing, and

shipping of blood, urine, and other types

of specimens. This section provides

information on all biospecimens

collected for 1999–2010.

MEC Laboratory Team

Each MEC had a laboratory

containing a bio-hood, complete blood

count (CBC) and differential analyzer,

two centrifuges, refrigerators, and

freezers. Each MEC laboratory team

included three medical technologists and

a certified phlebotomist. Staff was

certified in accordance with guidelines

set forth by the American Society for

Clinical Pathology. The medical

technologists’ tasks included:

performing CBCs, pregnancy tests, and

other tests; processing, storing, and

shipping specimens; assisting the

phlebotomist; and printing labels and

labeling vials. The chief medical

technologist was the most senior

member of the laboratory team and was

responsible for overseeing all laboratory

activities and performing quality control.

The phlebotomist’s tasks included:

administering a questionnaire to screen

for conditions that excluded sample

participants from the blood draw,

determining fasting status, conducting

the blood draw, administering the

glucose solution, and conducting a

second blood draw 2 hours after the

solution had been administered for the

oral glucose tolerance test.

Specific training for laboratory staff

was dependent upon the position.

However, all laboratory staff were

trained thoroughly to ensure that the

laboratory environment was safe.

Laboratory staff were aware of

hazardous chemicals that they worked

with, familiar with product labels and

other forms of warning, and

knowledgeable about how to handle

accidental exposures. The staff was

trained annually on each of the

following:

+	 Occupational Safety and Health

Administration (OSHA) Bloodborne

Pathogen Regulation

+	 NHANES exposure control plan

+	 Working safely with hazardous

chemicals

+	 Universal precautions and a set of

guidelines for preventing the

transmission of bloodborne

pathogens such as human

immunodeficiency virus (HIV) and

hepatitis viruses in health care

settings.

Biospecimen Collection

Biospecimens collected in the MEC

included blood, hair, nasal swab, oral

rinse, urine, and vaginal swab. Table M

lists all laboratory tests conducted for

1999–2010. Collection procedures

varied based on the specimen types.

Laboratories performed more than 545

different biochemical tests, which

provided detailed information about the

sample participant’s health and

nutritional status.

Blood

Blood was collected from sample

participants aged 1 and over. The

phlebotomist used a needle to draw

blood from a vein in the antecubital

fossa of the participant’s arm. The

amount of blood drawn varied by age

and survey year, but was not more than

128 mL for participants aged 12 and

over. Blood was processed and aliquoted

into vials for storage in the MEC. The

vials were then refrigerated or frozen

before transport to laboratories across

the United States. Most assays were

completed in remote laboratories, except

for the CBC and pregnancy tests, which

were done in the MEC. If permission

was granted, some specimens were

aliquoted into vessels and banked for

future studies, including genetic studies.

If excess serum remained after tests at

remote laboratories were completed, it

was shipped back to the NHANES

biorepositories and stored for future

research. This component was conducted

for 1999–2010.

Hair

A sample of hair was obtained and

analyzed for total mercury level. This

procedure consisted of the health

technician collecting approximately 100

strands from male and female sample

participants aged 1–5, and from females

aged 16–49. This component was

conducted for 1999–2001.

Nasal swab

A nasal swab was done to

understand the extent of Staphylococcus

aureus nasal colonization, including the

prevalence of methicillin-resistant

Staphylococcus aureus, or MRSA,

colonization. This procedure consisted

of the health technician inserting the

swab 2 cm into the nostril and rotating

for 3 seconds, then repeating the

procedure in the other nostril. This

component was conducted on sample

participants aged 1 and over for

2001–2004.
interviews: National Health and Nutrition Examination Survey, 1999–2010

Description Survey years

Lifetime and current use (past 12 months) 1999–2010

Fecal incontinence and defecating function 2005–2010Overall health assessment, quality of life (past 30 days), recent illness (past 30 days), blood donation, and HIV testing 1999–2010

Depression symptoms and impairment from depression symptoms; depression measured using the Patient Health Questionnaire 2005–2010(PHQ-9), a nine-item screening instrument that asks questions about the frequency of symptoms of depression over the past 2 weeks,

with a final follow-up question to assess overall impairment from depressive symptoms. Response categories ‘‘not at all,’’ several days,’’more than half the days,’’ and ‘‘nearly every day’’ were scored 0–3; a total score was calculated at 0–27. A score of 10 or higher has

been well-validated and commonly used in clinical studies to define depression; other methods for defining depression based on this

instrument were also usedFood and drink consumed in the home, restaurants, and other locations in past 30 days 2009–2010

Kidney disease, kidney stones, urinary incontinence, and nocturia 1999–2010

Pesticide use in the home and lawn or garden during the past 7 days 2005–2010Daily activities, leisure-time activities, and sedentary activities 1999–2010Prostate conditions and whether a rectal examination had been done to check for prostate cancer 2005–2008

Menstrual history, pregnancy history, lactation, oral contraceptive and hormone replacement therapy use, and other related conditions 1999–2010

Identified relationship of respondent to sample participant; also identified why sample participant could not respond (proxy), and gave 1999–2010

information on the use of interpreters and language used for the interviewUse of cigarettes, pipes, cigars, and other forms of tobacco, as well as nicotine replacement therapies (e.g., nicotine patches), in the past 1999–2010

5 days

Exposure to chemicals that are on priority toxicant or critical contaminant lists 2005–2010Self-perception of weight, reasons for losing weight, and methods used to lose weight 2005–2010

Lifetime and current use (past 12 months); questions not specific to type of alcohol used 1999–2010

Lifetime and current use of cocaine and other street drugs and intravenous use of illicit drugs 1999–2010

Household food security, individual food security, food stamp program benefits, and Women, Infants and Children program benefits 2005–2010

Prostate conditions, prostate cancer treatment, and erectile dysfunction 2001–2004

Lifetime and current sexual behavior for both men and women; major items included age at first sexual intercourse, number of sexual 1999–2010

partners, sexual orientation, circumcision status (men), and history of sexually transmitted diseases

Cigarette use, including history of use, age at initiation, current use, past 30-day prevalence, amount, cigarette brand, and other related 1999–2010

detailsComprises eight questions from the Diagnostic Interview Schedule for Children Predictive Scales (DPS) developed by the Columbia 1999–2004

University College of Physicians and Surgeons/New York State Psychiatric Institute in New York, N.Y., and focused only on those items

from the full Conduct Disorder module considered significant predictors of disorder; shown to determine adolescents who are at high

probability of meeting diagnostic criteria accurately

Detailed dietary intake information to estimate types and amounts of foods and beverages (including all types of water) consumed during 1999–2010

the 24-hour period prior to the interview (midnight to midnight), and to estimate intakes of energy, nutrients, and other food components

from those foods and beverages; following dietary recall, participants were asked questions on salt use, whether respondent is on anytype of special diet, frequency of fish and shellfish consumed during the past 30 days, and whether overall intake on the previous day

was much more than usual, usual, or much less than usual

Types and amounts of dietary supplements consumed during the 24-hour period prior to the interview (midnight to midnight) 2007–2010

Series 1, No. 56[ Page 17
Health and Nutrition Examination Survey, 1999–2010

Specimen Description Survey years

.............. Whole blood Chemical carcinogen used in synthetic fibers 2003–2010

.............. Urine Major protein in the body 1999–2010

.............. Urine Ratio of albumin to creatinine used to detect kidney disease progression 2009–2010

ulins ........... Serum Markers of immune response to allergens 2005–2006

.............. Serum Protein that binds to lipids and transports them in the body 2005–2010

.............. Urine Toxic heavy metal 2003–2010

.............. Urine Toxic heavy metal 2007–2010

.............. Swab Imbalance in bacteria normally found in the vagina 2001–2004

.............. Serum Panel of 23 clinical tests used to assess general health 1999–2010

.............. Serum Enzyme that removes phosphate from other molecules 1999–2004

.............. Whole blood Toxic heavy metal 1999–2010

.............. Urine Psychoactive stimulant 2009–2010

.............. Whole blood Cells that protect the body from infection 1999–2006

.............. Urine Sexually transmitted pathogen 1999–2010

.............. Whole blood Panel of 20 clinical tests used to assess general health 1999–2010

.............. Serum Metabolite of nicotine 1999–2010

.............. Serum Protein marker of insulin secretion 1999–2004

.............. Serum Protein produced in response to tissue damage and inflammation 1999–2010

. . . . . . . . . . . . . . Urine/serum Waste product of normal muscle breakdown 1999–2010

.............. Serum Intestinal parasite usually found in water 1999–2001

.............. Urine/serum Chemicals that repel or destroy pests (insects and rodents) 1999–2010

.............. Urine/serum Chemicals that destroy fungi 1999–2010

.............. Urine/serum Chemicals that destroy plants 1999–2010

ent pesticides ..... Serum Synthetic chemicals that persist as environmental pollutants 1999–2010

.............. Dust Toxins associated with certain bacteria 2005–2006

olic compounds.... Urine Chemicals that repel or destroy pests (insects and rodents) 1999–2010

.............. Urine Natural and synthetic chemicals containing phenol that may be toxic 1999–2010

.............. Urine Synthetic preservatives that may cause hormone disruption 2005–2010

.............. Whole blood Protein used in the synthesis of hemoglobin in the red blood cell 1999–2006

.............. Plasma Synthetic fat found in food that raises LDL cholesterol and lowers HDL cholesterol 2007–2010

.............. Serum Iron stored in the body 1999–2010

.............. Plasma Coagulation protein 1999–2002

.............. Urine Measure of urine quantity produced in a specified time period 2009–2010

.............. Whole blood Vitamin important in the formation of red blood cells 1999–2010

.............. Serum Vitamin important in the formation of red blood cells 1999–2010

.............. Serum Hormone that regulates ovarian function 1999–2002

.............. Plasma Amount of sugar in the blood 1999–2010

.............. Whole blood Measure of average blood glucose in the past 2 to 3 months 1999–2010

.............. Urine Sexually transmitted disease pathogen 1999–2008

.............. Serum Bacterium that causes stomach ulcers 1999–2001

.............. Serum Indicates previous exposure to hepatitis B infection, or vaccination 1999–2010

.............. Serum Indicates hepatitis B infection 1999–2010

.............. Serum Serologic tests for antibody to viruses that cause liver disease 1999–2010

otype .......... Serum Serologic tests to identify Hepatitis C RNA and genotypes 2007–2010

.............. Serum Serologic tests to identify Hepatitis C RNA and genotypes 2009–2010

.............. Serum Antibodies to herpes virus 1999–2010

.............. Urine Antibodies to herpes virus 1999–2010

.............. Serum Antibody to HIV 1999–2010

.............. Serum Antigen found in blood associated with a number of inflammatory conditions 2009 only

.............. Plasma Amino acid in the blood that can be a risk factor for cardiovascular disease 1999–2006

.............. Oral rinse Virus that infects the skin and may cause cancer 2009–2010

.............. Serum Virus that infects the skin and may cause cancer 2002–2010

Page 18[ Series 1, No. 56
Health and Nutrition Examination Survey, 1999–2010—Con.

Specimen Description Survey years

.............. Swab Virus that infects the skin and may cause cancer 2002–2010

.............. Dust Any substance found in the bed or bedroom that can cause an allergic reaction 2005–2006

.............. Serum Hormone that regulates glucose metabolism 1999–2010

.............. Urine Element that is a component of thyroid hormones 2000–2010

. . . . . . . . . . . . . . Serum Mineral the body needs to make red blood cells 1999–2006

.............. Serum Natural or synthetic emulsion of polymer microparticles 1999–2001

.............. Whole blood Toxic metal that can affect physical and mental development 1999–2010

.............. Dust Lead that is recovered from household dust 1999–2004

.............. Serum Lipid panel showing concentrations of lipids in the blood 1999–2010

.............. Serum Low-density lipoprotein that is a risk factor for atherosclerotic disease 2005 only

.............. Serum Markers of immunization status 1999–2004

) ............. Serum Markers of immunization status 2009–2010

.............. Whole blood Toxic heavy metal 1999–2010

.............. Hair Toxic heavy metal 1999–2001

.............. Urine Toxic heavy metal 1999–2010

.............. Plasma Elevated levels may indicate Vitamin B12 deficiency 1999–2004

.............. Swab Methicillin-resistant Staphylococcus aureus (a bacteria resistant to the antibiotic methicillin) 2001–2004

.............. Urine Toxic heavy metals detected in urine 1999–2010

.............. Urine Metabolite of nicotine 2007–2010

.............. Urine Breakdown product of collagen, used as a marker of bone turnover 1999–2002

.............. Plasma Oral glucose tolerance test to determine how quickly glucose is cleared from the blood 2005–2010

.............. Plasma Polyunsaturated fat found in food, which has been shown to lower the risk of cardiovascular 2007–2010

disease

.............. Serum Diverse synthetic insecticides that are persistent in the environment 1999–2010

.............. Urine Diverse synthetic insecticides that are persistent in the environment 1999–2010

.............. Urine Measure of urine concentration 2009–2010

.............. Serum Hormone that regulates calcium absorption and converts vitamin D to its active form 2003–2006

.............. Urine Chemical that interferes with iodine uptake by the thyroid gland 2005–2010

. . . . . . . . . . . . . . Water Three toxicologically related analytes that affect thyroid function 2005–2008

.............. Urine Nitrate is a component of fertilizer that is a groundwater pollutant; thiocyanate is a compound 2007–2010

in tobacco smoke

.............. Urine Chemicals used in plastic that have been shown to change hormone levels 1999–2010

.............. Urine Naturally occurring nonsteroidal plant compounds that are similar to estrogen 1999–2010

. . . . . ......... Urine Atmospheric pollutants produced as byproducts of burning fuel 1999–2010

.............. Serum Flame retardants that bio-accumulate and may cause hormone-disrupting effects 2003–2010

.............. Serum Persistent organic pollutants 2003–2010

.............. Urine Hormone diagnostic for pregnancy 1999–2010

.............. Serum Protein produced by the prostate gland that is elevated in prostate conditions 2001–2010

. . . . . . . . . . . . . . Serum Prostate-specific antigen complexed to proteins 2007–2010

.............. Serum Essential micronutrient that catalyzes enzyme reactions 1999–2004

.............. Serum/urine/plasma Residual sera used for special studies 1999–2010

.............. Serum Selected reaction monitoring (SRM) is a method of chromatography resulting in highly specific 2003–2010

quantification of analyte

.............. Serum Tests that detect syphilis, a sexually transmitted pathogen 2001–2004

.............. Serum Tests to assess thyroid function 1999–2002

APO, TSH). . . . . . . Serum Tests to assess thyroid function 2005–2010

.............. Serum Test that determines iron-binding capacity 1999–2006

.............. Serum Antibodies to a parasite that can cause illness in humans 1999–2004

.............. Serum Carrier protein for transferrin 2003–2010

.............. Serum Ratio of serum iron and total iron-binding capacity, multiplied by 100 1999–2006

.............. Swab Parasite that causes vaginal infection 2001–2004

tibodies ........ Serum Markers of celiac disease 2009–2010

.............. Serum Nutrient vitamins required for retinal function that act as antioxidants 1999–2006

Series 1, No. 56[ Page 19
Health and Nutrition Examination Survey, 1999–2010—Con.

Specimen Description Survey years

.............. Serum Part of the vitamin B-complex that acts as an enzyme cofactor in amino acid metabolism 2003–2010

.............. Serum Part of the vitamin B-complex involved in cell metabolism and DNA synthesis 1999–2006

.............. Serum Nutrient vitamin that acts as an enzyme cofactor and antioxidant 2001–2006

.............. Serum Nutrient vitamin produced in the skin after absorption of ultraviolet light 1999–2010

.............. Whole blood Toxic volatile organic compounds 1999–2010

.............. Air monitor

Measures environmental exposure to toxic volatile organic compounds 1999–2001

.............. Water Toxic volatile organic compounds found in residential water 1999–2010

.............. Whole blood White blood cells used to extract DNA 1999–2002,

2007–2010

Page 20 [ Series 1, No. 56
Series 1, No. 56 [ Page 21

Oral rinse

An oral rinse was collected and

tested for the presence of multiple types

of human papillomavirus (HPV). The

examining dentist instructed sample

participants aged 14–69 to gargle with

mouthwash for 30 seconds and then spit

into a specimen container. This

component was conducted for

2009–2010.

Urine

Urine was collected for the

following purposes: (a) to do a urine

pregnancy test on female participants

aged 12–59 and menstruating females

aged 8–11, (b) to aliquot, store, and

transport to multiple laboratories for

analysis, (c) to aliquot and bank for

future studies, and (d) to do a backup

HIV test if the amount of blood

collected was insufficient for HIV

testing. Participants aged 6 and over

were asked to provide random urine by

voiding into specimen cups. The amount

collected varied. This component was

conducted for 1999–2010.

Vaginal swab

Female participants aged 14–59

were asked to self-collect a vaginal

specimen using a sterile swab. The

vaginal swab was tested for the presence

of multiple types of HPV. In privacy, the

participant inserted the swab and turned

the foam tip against the walls of the

vagina while counting to 10. The swab

was removed without touching the skin

or hair outside of the vagina and placed

back into its original container. This

component was conducted for

2002–2010.

Oral Glucose Tolerance

Test

The oral glucose tolerance test

(OGTT) was conducted on sample

participants aged 12 and over who were

examined in the morning session and

had completed at least a 9-hour fast.

After the initial blood draw, participants

were asked to drink 75 grams of

dextrose (10 oz. of glucose solution)

within 10 minutes. Two hours later, a

second blood sample was drawn. The

inclusion of OGTT provided information

on the extent of impaired glucose

tolerance, or IGT, and diabetes in the

U.S. population. This component was

conducted for 2005–2010.

Biospecimen Processing

and Shipping

Specimens were labeled with a

number that corresponded to the

participant’s sample number. Labels

were generated and affixed to vials. This

allowed for tracking specimens from

MEC processing through receipt in the

contract laboratory. All vials were

secured to prevent leakage and

evaporation. Specimen processing

varied. For example, blood processing

included centrifuging and storing blood

collection tubes; aliquoting whole blood

into vials; centrifuging, separating, and

aliquoting plasma and serum into vials;

performing dilutions; and washing and

lysing, or deconstructing, whole blood

cells. All specimens were immediately

stored at –20°C or refrigerated at

4°–8°C. Once processed, specimens

were shipped to a variety of contract

laboratories. Wet or dry ice was used if

necessary for shipping. Each shipment

included a copy of a shipping manifest.

Most specimens were packed and

shipped once a week.

Quality Assurance and

Quality Control

The NHANES MEC laboratory was a

Clinical Laboratory Improvement Actcertified laboratory of moderate complexity.

Quality assurance and quality control

(QA/QC) involved both internal and

external surveillance. QA/QC procedures

were performed in the MEC as well as in

contract laboratories. As part of the overall

QA process, all collection materials,

vacuum sample vials, and storage

containers used were initially prescreened

for background contamination levels of

blood lead, cadmium, and mercury; and

urinary heavy metals, arsenic, iodine, and

mercury. EDTA (ethylenediaminetetraacetic

acid) tubes were used after prescreening

confirmed that they had no contamination.

The lot number and expiration dates for all

vacuum sample vials, needles, and reagents

were recorded.

Specific QC procedures were

followed in the laboratory as well. For

example, the freezers, refrigerators, and

centrifuges were cleaned before the

MEC opened, and a temperature reading

on these items was conducted daily.

On-site calibrations were performed

twice each year. The NCHS biomedical

engineer certified the revolutions per

minute (rpm) of the centrifuges

periodically and replaced the highefficiency particulate air (HEPA) filters

as necessary. All instrument maintenance

was recorded. NHANES laboratories

participated in the College of American

Pathologists (CAP) proficiency-testing

program. CAP samples were sent three

times a year for the CBC and qualitative

serum human chorionic gonadotropin

(hCG). In addition, blind split samples

were used for QC determinations.

Contract laboratories followed their

QA/QC guidelines when working with

NHANES specimens. However, to

ensure QA/QC, NHANES staff

conducted annual laboratory inspections

and reviewed the QC data from each

laboratory.

Post-MEC Data

Collection

At the conclusion of their MEC

appointment, sample participants were

recruited to participate in post-MEC

data collection activities (Table N).

Eligibility for post-MEC data collection

depended on the sample participant’s

age and gender and whether he or she

completed the required components.

Sample participants who also

participated in any of the post-MEC

data collection activities received

additional remuneration, summarized in

Table N.

Post-MEC data collection activities

for 1999–2010 included:

+	 Allergen dust collection

+	 Dietary telephone follow-up

+	 Flexible consumer behavior survey

(FCBS)

+	 Food frequency questionnaire

+	 Hepatitis C follow-up questionnaire
Page 22 [ Series 1, No. 56

+	 Home urine collection

+	 Parent interview of the computer

diagnostic interview schedule for

children (CDISC)

+	 Physical activity monitor (PAM)

+	 Prostate-specific antigen, or PSA,

follow-up questionnaire

+	 Tuberculin (TB) skin test reading

+	 Volatile organic compound (VOC)

exposure monitor

Allergen Dust Collection

The allergen dust collection

component collected bed and floor dust

samples to obtain data on allergens and

endotoxins. All households that had

sample participants aged 1 and over

who completed the MEC examination

were eligible. This component was

collected for 2005–2006.

Dietary Interview

Follow-up

To obtain a more complete picture

of the usual dietary intake of the U.S.

population, a second 24-hour dietary

interview of participants was done by

telephone. This questionnaire took

approximately 30–40 minutes and was

conducted 3–10 days after the sample

participant’s MEC exam. All sample

participants aged 1 and over who

completed the MEC dietary interview

were eligible to participate. Proxy

interviews were conducted for children

aged 1–11. This interview was

conducted for 2002–2010.

Flexible Consumer

Behavior Survey

The FCBS was a 15-minute

telephone interview that collected

information on the sample participant’s

knowledge, attitude, and beliefs

regarding food nutrition and food

choices. All sample participants were

eligible if they completed the first part

of the FCBS during the household

interview, and the dietary interview in

the MEC. This interview was conducted

for 2007–2010.

Table N. Post-MEC examinations: National Health and Nutrition Examination Survey,

1999–2010

Component name	 Survey years Remuneration amount

Allergen dust collection .............. 
 

Dietary phone follow-up .............. 
 

Flexible consumer behavior survey ....... 
 

Food frequency ................... 
 

Hepatitis C follow-up ................ 
 

Home urine collection ............... 
 

Parent composite international diagnostic
 

interview ...................... 
 

Physical activity monitor .............. 
 

Prostate-specific antigen follow-up ....... 
 

Tuberculin skin test ................. 
 

VOC exposure monitor............... 
 

2005–2006 $50 per family

2002–2010 $30 per participant

2007–2010 $15 per participant

2003–2006 $30 per participant

2001–2010 –

2009–2010 $40 per participant

2000–2004 $30 per participant

2003–2006 $40 per participant

2003–2006 –

1999–2000 $30 per participant

1999–2001 $15 per participant

– Quantity zero.
 

NOTES: MEC is mobile examination center. VOC is volatile organic compound.
 

Food Frequency

Questionnaire

The food frequency questionnaire

collected information on how often

certain foods were consumed. The

questionnaire was sent by mail to

examined sample participants aged 2

and over and took approximately 20–30

minutes to complete. This questionnaire

was used for 2003–2006.

Hepatitis C Follow-up

The hepatitis C follow-up was a

telephone questionnaire conducted on

sample participants who tested positive

for hepatitis C, to obtain information on

their knowledge about their infection

and follow-up after notification. The

hepatitis C follow-up took place 6

months after the NHANES examination

and was approximately 20 minutes in

duration. There was no remuneration for

participation. This questionnaire was

used for 2001–2010.

Home Urine Collection

The home urine collection was done

within 10 days of a sample participant’s

MEC exam. Sample participants aged 6

and over were eligible. The first

morning void was collected in a

collection cup provided to the sample

participant. The specimen was mailed to

the laboratory for analysis. See the

preceding section on ‘‘MEC

Biospecimen Collection’’ for more

information on the NHANES laboratory.

This component was collected for

2009–2010.

Parent Interview of

Computerized Diagnostic

Interview Schedule for

Children

The parent interview of the CDISC

was a telephone follow-up for the parent

or guardian of select children, aged

8–15, who participated in the CDISC in

the MEC. The parent interview of the

CDISC took approximately 30 minutes

depending on the case. The parent

interview was conducted 4–28 days after

the child’s MEC exam. This interview

was conducted for 2000–2004.

Physical Activity Monitor

The PAM component was

conducted to assess physical activity

levels for sample participants aged 6

and over. Sample participants were

asked to wear the PAM for 7 days. After

the 7 days, the sample participant

mailed the PAM to the contractor home

office. This component was conducted

for 2003–2006.

Prostate-specific Antigen

The PSA follow-up was a telephone

questionnaire conducted on men with

high PSA test results, to obtain

information on their knowledge of PSA

and follow-up after notification. The

PSA follow-up took place 6 months

after the NHANES examination and was
Series 1, No. 56 [ Page 23

approximately 15 minutes in duration.

There was no remuneration for

participation. This questionnaire was

asked for 2003–2006.

Tuberculin Skin Test

Reading

The TB skin test required a

follow-up appointment to measure the

reaction. The test measurement took

place 46–54 hours after the antigen was

placed under the skin of sample

participants aged 1 and over. This

reading was conducted for 1999–2000.

Volatile Organic

Compound Exposure

Monitor

The VOC exposure monitor data

were collected to measure environmental

exposure to toxic VOCs. Selected

sample participants aged 20–59 wore

small, lightweight passive sampling

badges for 48 hours, beginning once

they left the MEC. Sample participants

returned with the badge and a sample of

tap water from their homes. They also

had a second blood draw when they

returned the monitor and the water

sample. This component was conducted

for 1999–2001.

Report of Findings

Health measurements and laboratory

test results were provided to all sample

participants who completed the MEC

exam. The NHANES Physician

Advisory Group determined which

results should be reported back to

participants, and how this should be

done. Reporting protocols were

reviewed and approved by the NCHS

Research Ethics Review Board (ERB);

for more information on the ERB, see

the ‘‘Ethical, Privacy, and

Confidentiality Considerations’’ section.

The reports provided to sample

participants were called Reports of

Findings.

A preliminary Report of Findings

was given to participants at the

conclusion of their MEC exam. This

preliminary report included a letter of

gratitude and all examination results that

could be recorded in the MEC.

Examples of such results included blood

pressure, height and weight, and a

complete blood count (CBC).

If abnormal findings were

discovered during a MEC examination,

the physician discussed these findings

with the sample participant. The

physician also made referrals if

necessary. In general, there were three

levels of examination findings and

associated referrals.

Level I Finding

(Emergency)

A Level I finding was a medical

emergency, for example, a dangerously

high systolic blood pressure or seizure.

The MEC physician managed medical

emergencies. An emergency medical kit

was available in each MEC so that

emergency stabilization could be

performed. However, the preferred

method of handling medical

emergencies was to contact local rescue

squads, ambulance services, and hospital

emergency rooms. The telephone

numbers for local emergency services

were posted in the MEC. A Level I

finding was rare.

Level II Finding (Early

Report)

A Level II finding required the

participant to follow up with his or her

regular doctor within 2 weeks. These

findings were detected either at the

MEC or after the examination when

laboratory results were sent from the

laboratories. The MEC physician

evaluated these findings, such as an

abnormality in the CBC, and counseled

sample participants before they left the

examination center. The physician also

provided the sample participant with a

written report of the condition and urged

the participant to make an appointment

with his or her primary care physician

within the next 2 weeks. If the

participant had no primary care

physician, the MEC physician had

access to a list of providers or clinics

where the participant could be evaluated

at no charge, or on a sliding-scale fee

schedule.

Level II findings also occurred

when a laboratory or contractor

discovered abnormalities based on

NHANES early reporting thresholds.

Laboratories transmitted results that met

the threshold for early reporting

immediately by uploading results to a

secure FTP site or e-mailing the results

for import. Once abnormal findings

were received, an early reporting letter

describing the finding was sent to the

sample participant (or parent, if a

minor), urging the participant to see a

medical provider for evaluation. The

participant also had the option to talk

with the DHANES medical officer. This

type of Level II referral usually

occurred within 3 weeks after the

examination. Again, it was

recommended that the participant follow

up with his or her regular doctor within

2 weeks of receiving the early report

with laboratory abnormalities.

Level III Finding (Routine)

A Level III finding was the routine

Report of Findings (i.e., the Final

Report of Findings) provided to all

sample participants approximately 3–4

months after their examination date.

This report was mailed to sample

participants and included a letter of

gratitude, all final examination results,

and a laboratory glossary that helped

participants to understand their blood

results. Contact information for a

DHANES medical officer was also

provided should the participant have

questions.

Reporting Procedures for

Minors

The procedure to report results to

minors was similar to that for reporting

results to adult sample participants. If a

parent or guardian accompanied a minor

to the MEC, the preliminary Report of

Findings was given to the parent or

guardian. Any abnormal findings were

communicated to the parent or guardian,

and when applicable, NHANES staff

requested permission from the parent or
Page 24 [ Series 1, No. 56

guardian to contact the minor’s primary

care physician.

If a parent or guardian did not

accompany a minor to the MEC, and if

there were any abnormal results,

NHANES notified the parent or

guardian as follows:

+	 For a Level I finding, the MEC

physician immediately called the

parent or guardian.

+	 For a Level II referral, the MEC

physician called the parent or

guardian to inform him or her and

to obtain consent to notify the

minor’s primary care physician. The

MEC physician also gave the parent

or guardian a list of providers in the

area who could assist in evaluation

and treatment.

Reporting Procedures for

Sexually Transmitted

Diseases and HIV

The reporting of sexually

transmitted diseases (STDs) and HIV

test results was handled differently from

other NHANES examination findings.

STD and HIV test results were provided

to sample participants by telephone.

Because of the medical, social, and

emotional consequences of positive STD

and HIV tests, disclosure of results was

handled such that counseling was

provided at the time results were given.

At the time of the MEC

examination, the physician provided

STD and HIV pretest counseling. The

physician explained the purpose of the

testing, the reporting procedures, and the

confidentiality assurances. The

participant could decline the STD or

HIV testing at this point.

If the sample participant agreed to

the STD and HIV testing, the physician

asked the sample participant to provide

a password to be used when results

were given later. This password was

entered into the database. Before leaving

the MEC, sample participants were

given a paper with a toll-free number,

their password, and the date after which

their test results were available

(approximately 3–4 weeks after the

examination). The sample participant

was instructed not to share the

information with anyone and to call for

the test results after the stated date.

Adolescents aged 14–17 were

instructed to call for their results the

same way as adults. Results, whether

positive or negative, were given to the

sample participant over the telephone

after the sample participant provided the

DHANES STD and HIV counselor with

a password. Adolescents who did not

call for their findings within a 10-day

period of the designated dates were

notified by telephone. Three attempts

were made to contact the adolescent.

Adults who did not call for their

findings within a 10-day period of the

designated dates were sent a reminder

letter from DHANES. If the adult

sample participants did not call within a

10-day period after the reminder letter

was sent, a second notification letter

was sent again reminding them to call

DHANES to get their test results. If

there was no response after 10 days

from the second mailing, a third and

final letter was sent.

Results of STD or HIV tests were

not put in writing with the sample

participant’s name or any other personal

identifiers, unless the participant

requested that the findings be mailed to

them. STD results, including HIV, were

given in both English and Spanish.

DHANES staff who provided results

completed a 3-day course on sexually

transmitted infections and were HIV

counseling certified.

Data Processing and

Information

Technology

Information technology (IT) played

a vital role in the success of NHANES.

The vision for NHANES 1999–2010

was to automate as much of the data

collection as possible. Objectives

included verification of data, utilization

of common data elements across

components and cycles, reduction of

burden on the participant, and minimal

post-data collection editing. The

requirements for automation were to:

+	 Maintain an audit trail for data and

systems modifications.

+	 Ensure configuration management in

the form of version control over all

applications.

+	 Allow for maximum use of

commercial off-the-shelf, or COTS,

equipment and software.

+	 Produce formatted and structured

documentation available online.

+	 Permit a graphical user interface and

point of entry validation.

+	 Ensure a flexible system structure.

+	 Develop systems compatible with

Microsoft Windows.

+	 Design security functions into all

system processes.

+	 Permit the timely delivery of data

from the point of origin to secure

storage.

Architecture

In 1999, NHANES developed the

Integrated Survey Information System

(ISIS), a comprehensive architecture for

data collection. Since ISIS was

introduced, automated data collection

and reporting of interview, examination,

and laboratory data has been completed

for 177 NHANES sites across the

United States. ISIS included a private

wide area network, or WAN, and a

client–server environment with data

replication, providing a built-in disaster

recovery system. The infrastructure

supported changes in survey

requirements as needed and was

upgraded when necessary, for example,

when new equipment was required for

data collection or when security or other

system requirements changed.

ISIS used different computing

platforms at different points in the data

collection process. Tablet personal

computers were used by interviewers to

collect household interview data, and

data were encrypted during all

transmissions between the servers in the

MEC trailers, the field office, contractor

offices, and NHANES’ home office.

Workstations and database servers were

used for database access, data

manipulation, review, and numerous

other processes. Hardware and software
Series 1, No. 56 [ Page 25

were upgraded and replaced as

requirements changed and IT

capabilities advanced.

Data Collection and

Processing

NHANES data collection

instruments were automated systems that

integrated biomedical equipment,

questionnaire items, and other data

collection and administrative systems, to

provide reliable and efficient electronic

data capture. All instruments were tested

for accuracy, calibration, and adherence

to protocols. Data from these automated

systems underwent stringent review to

confirm the accuracy of the data and the

data collection software, as well as

compliance with data confidentiality

requirements. All collected data were

stored in an analytic database, and the

data from all components were linked

internally by a common identifier.

Because NHANES’ reputation

depends on maintenance of the

confidentiality of all survey participants,

all collected and stored NHANES data

were protected with a high level of

security, including encryption of the

data. NHANES data were protected

from loss through a system of regular

automated backups and secure off-site

storage, and NHANES maintained

formal processes for disaster recovery

and business continuity in compliance

with federal regulations.

Data Release

At the conclusion of every 2-year

cycle, NHANES data were released to

the public. Data were edited to provide

consistency and accuracy, and to

preserve confidentiality. All direct

personal identifiers, as well as any

characteristics that could lead to

identification, were omitted from the

data sets. Data were reviewed by the

NCHS Disclosure Review Board (DRB),

and based on any recommendations

from DRB, the data were then further

edited. All data were released in a

SAS-readable and -transportable format.

Documentation describing edits to the

data, and a codebook of data items,

were provided for each component. All

released data were available on the

NHANES website. Some data items

were not released publicly due to

confidentiality or data quality issues.

Data not released due to confidentiality

restrictions were accessible via the

NHCS Research Data Center (RDC)

through a proposal process, and subject

to availability and approval. For more

information on NCHS RDC, visit

http://www.cdc.gov/rdc/.

Data Usability

A standardized variable naming

convention was developed to help

researchers use the NHANES data sets.

This naming convention consisted of

each variable having an eight-character

name, with defined positions having

specific meanings. Positions 1 and 2

represented the topic or subject. For

example, the variable name for the urine

pregnancy test was URXPREG. The

‘‘UR’’ in positions 1 and 2 indicated

that the variable concerns urine, and the

‘‘X’’ in position 3 indicated that this is

an examination variable. Other data

types were indicated by other letters:

Q = questionnaire, A = administrative,

S = sampling, C = first random repeat

quality-control items, G = gold standard

quality-control repeat items, I =

item-level components, and D =

modified data items. For further

information on how to analyze the data,

visit http://www.cdc.gov/nchs/tutorials/.

Conclusion

This NHANES plan and operations

1999–2010 report provides an overview

of the conduct of NHANES in a single

document. For more detailed

information on NHANES, see the

NHANES website at www.cdc.gov/

nhanes. Planning and implementing

NHANES 1999–2010 involved

numerous organizations and

partnerships, and these collaborations

were critical to the success of the

survey.

NHANES has been in operation for

more than 50 years and collects

high-quality health data. It is a unique

survey in that it collects demographic,

diet, medical, and behavioral data. It has

remained responsive to new public

health needs while maintaining the core

measurements necessary for ongoing

monitoring of our nation’s health.

NHANES data have produced valuable

tools, such as pediatric growth charts,

which provide information on growth of

infants and children. NHANES data

have also supported national health

initiatives and have been used to assist

in policy decisions. NHANES continues

to provide data on public health thanks

to the thousands of Americans who

participate each year.

References

1.	 National Center for Health Statistics.

Origin, program, and operation of the

U.S. National Health Survey. National

Center for Health Statistics. Vital

Health Stat 1(1). 1965.

2.	 Centers for Disease Control and

Prevention. Changing methods of

NCHS surveys: 1960–2010 and

beyond. MMWR Surveill Summ 60

Suppl 4:42–8. 2011. Available from:

http://www.cdc.gov/mmwr/preview/

mmwrhtml/su6004a8.htm.

3.	 National Center for Health Statistics.

The National Health Examination

Surveys, (NHES I) 1959–1962.

Public-use data file documentation.

Hyattsville, MD. Available from:

ftp://ftp.cdc.gov/pub/health_statistics/

NCHS/nhanes/nhes123/hesi.pdf.

4.	 National Center for Health Statistics.

The National Health Examination

Surveys, (NHES II) 1963–1965.

Public-use data file documentation.

Hyattsville, MD. Available from:

ftp://ftp.cdc.gov/pub/health_statistics/

NCHS/nhanes/nhes123/hesii.pdf.

5.	 National Center for Health Statistics.

The National Health Examination

Surveys, (NHES III) 1966–1970.

Public-use data file documentation.

Hyattsville, MD. Available from:

ftp://ftp.cdc.gov/pub/health_statistics/

NCHS/nhanes/nhes123/hesiii.pdf.

6.	 Engel A, Murphy RS, Maurer K,

Collins E. Plan and operation of the

HANES I Augmentation Survey of

adults 25–74 years: United States,

1974–1975. National Center for Health

Statistics. Vital Health Stat 1(14). 1978.

Available from: http://www.cdc.gov/

nchs/data/series/sr_01/sr01_014.pdf.
Page 26 [ Series 1, No. 56

7.	 Curtin LR, Mohadjer LK, Dohrmann

SM, et al. The National Health and

Nutrition Examination Survey: Sample

design, 1999–2006. National Center for

Health Statistics. Vital Health Stat

2(155). 2012.

8.	 Curtin LR, Mohadjer LK, Dohrmann

SM, et al. The National Health and

Nutrition Examination Survey: Sample

design, 2007–2010. National Center for

Health Statistics. Vital Health Stat

2(160). Forthcoming.

9.	 Centers for Disease Control and

Prevention. Certificates and assurances

of confidentiality. Available from:

http://www.cdc.gov/od/science/integrity/

confidentiality/.
Series 1, No. 56 [ Page 27

Appendix. Glossary

Aliquoting—Dividing the blood into

equal parts over several vials.

Centrifugation—The process of

putting biological samples into an

instrument that spins around a central

axis to separate materials into different

layers with centrifugal force. All work

was performed under the laminar-flow

biological safety cabinet, using only

those materials that the Centers for

Disease Control and Prevention had

prescreened for possible contamination.

Ethics Review Board—In 2003, the

National Health and Nutrition

Examination Survey (NHANES)

Institutional Review Board changed its

name to the National Center for Health

Statistics (NCHS) Research Ethics

Review Board.

Group quarters—A place where

people live or stay that is normally

owned or managed by an entity or

organization providing housing or

services for the residents. These services

may include custodial or medical care,

as well as other types of assistance, and

residency is commonly restricted to

those receiving these services. People

living in group quarters are usually not

related to each other. Group quarters

include such places as college residence

halls, residential treatment centers,

skilled nursing facilities, group homes,

military barracks, correctional facilities,

workers’ dormitories, and facilities for

people experiencing homelessness.

These are generally grouped into two

categories: institutional group quarters

and noninstitutional group quarters.

Institutional group quarters—Group

quarters providing formally

authorized, supervised care or

custody in institutional settings,

such as correctional facilities;

nursing and skilled nursing

facilities; inpatient hospice facilities;

mental facilities (psychiatric

hospital); group homes for

juveniles; and residential treatment

centers for juveniles. Institutional

group quarters are not included in

the NHANES sample. (For group

quarters included in NHANES, see

Noninstitutional group quarters.)

Noninstitutional group quarters—

Group quarters that do not provide

formally authorized, supervised care

or custody in institutional settings.

These include college or university

housing, group homes intended for

adults, residential treatment

facilities for adults, workers’ group

living quarters, Job Corps centers,

and religious group quarters.

Noninstitutional group quarters are

included in the NHANES sample.

Household—The person or group of

persons living in an occupied dwelling

unit.

Low income—Beginning in 2000,

NHANES split the sampling domains

for white persons and others based on

their income status: low income or

non-low income. Low-income persons

are those at or below 130% of the

federal poverty level. The poverty

threshold used in this determination was

based on the most recent poverty

guidelines published by the U.S.

Department of Health and Human

Services; these thresholds are updated

annually by the U.S. Census Bureau.

National Center for Health

Statistics (NCHS)—As the nation’s

principal health statistics agency, NCHS

designs, develops, and maintains a

number of systems that produce data

related to demographic and health

concerns. These include data on

registered births and deaths collected

through the National Vital Statistics

System, and data collected by the

National Health Interview Survey,

NHANES, the National Health Care

Surveys, and the National Survey of

Family Growth, among others. NCHS is

part of the Centers for Disease Control

and Prevention, an operating division of

the U.S. Department of Health and

Human Services (HHS).

National Office of Vital Statistics—

Part of the U.S. Public Health Service

since transferring from the U.S. Bureau

of the Census in 1946, the National

Office of Vital Statistics was responsible

for producing national vital statistics on

births, deaths, fetal deaths, marriages,

and divorces. In 1960, HHS merged this

office with the National Health Survey

program to form NCHS.

Noninstitutionalized civilian

population—Includes all people living

in households and excludes those

persons in institutional group quarters

and those on active duty with the

military. This is the target population for

NHANES.

Occupational Safety and Health

Administration (OSHA)—The main

federal agency charged with enforcing

safety and health legislation. OSHA

promulgated two standards relating to

the safe use of chemicals in the

workplace: ‘‘Hazard Communication’’

(29 CFR 1910.1200) and ‘‘Occupational

Exposure to Hazardous Chemicals in

Laboratories’’ (29 CFR 1910.1450). For

more information on these standards,

visit http://www.osha.gov/law-regs.html.

Primary sampling unit (PSU)—The

first-stage selection unit in a multistage

area probability sample. In NHANES,

PSUs are counties or groups of counties

in the United States. Some PSUs are so

large that they are selected into the

survey with a probability of one. These

are referred to as PSUs selected with

certainty (‘‘certainty PSUs’’); all other

PSUs are selected without certainty

(‘‘noncertainty PSUs’’).

Sample weight—The estimated

number of persons in the target

population that an NHANES respondent

represents. For example, if a man in the

sample represents 12,000 men in his

race and ethnicity-income-age category,

then his sample weight is 12,000. The

NHANES sample weights were adjusted

for different sampling rates (of the race

and ethnicity-income-age-sex groups),

different response rates, and different

coverage rates among persons in the

sample, so that accurate national

estimates can be made from the sample.

The product of all of these adjustments

is sometimes called the ‘‘final’’ sample

weight.
Page 28 [ Series 1, No. 56

Screener—An interview (usually

short) containing a set of questions

asked of a household member to

determine whether the household

contains anyone eligible for the survey.

In NHANES, the screener consisted of

compiling a household roster and

collecting the income level of the

household and the race and ethnicity,

age, and sex of all household members.

In NHANES, only persons aged 18 and

over can answer the screener.

Screening—The process of

conducting, or attempting to conduct,

the screening interview in the selected

dwelling units. Occupied dwelling units

(households) are screened through the

screening interview. Other units can also

be screened; the process for these units

is simply verification that they are

vacant or that they are not dwelling

units. See Screener.

Segment—A group of housing units

located near one another, all of which

were considered for selection into the

sample. For NHANES, segments consist

of a census block, or groups of blocks,

and their selection makes up the second

stage of sampling for NHANES. Within

each segment, a sample of dwelling

units was selected.

Weight—See Sample weight.
Vital and Health Statistics

Series Descriptions

ACTIVE SERIES

Series 1.	 Programs and Collection Procedures—This type of report

describes the data collection programs of the National Center

for Health Statistics. Series 1 includes descriptions of the

methods used to collect and process the data, definitions, and

other material necessary for understanding the data.

Series 2.	 Data Evaluation and Methods Research—This type of

report concerns statistical methods and includes analytical

techniques, objective evaluations of reliability of collected

data, and contributions to statistical theory. Also included are

experimental tests of new survey methods, comparisons of

U.S. methodologies with those of other countries, and as of

2009, studies of cognition and survey measurement, and final

reports of major committees concerning vital and health

statistics measurement and methods.

Series 3.	 Analytical and Epidemiological Studies—This type of

report presents analytical or interpretive studies based on vital

and health statistics. As of 2009, Series 3 also includes

studies based on surveys that are not part of continuing data

systems of the National Center for Health Statistics and

international vital and health statistics reports.

Series 10.	 Data From the National Health Interview Survey—This

type of report contains statistics on illness; unintentional

injuries; disability; use of hospital, medical, and other health

services; and a wide range of special current health topics

covering many aspects of health behaviors, health status, and

health care utilization. Series 10 is based on data collected in

this continuing national household interview survey.

Series 11.	 Data From the National Health Examination Survey, the

National Health and Nutrition Examination Surveys, and

the Hispanic Health and Nutrition Examination Survey—

In this type of report, data from direct examination, testing,

and measurement on representative samples of the civilian

noninstitutionalized population provide the basis for (1)

medically defined total prevalence of specific diseases or

conditions in the United States and the distributions of the

population with respect to physical, physiological, and

psychological characteristics, and (2) analyses of trends and

relationships among various measurements and between

survey periods.

Series 13.	 Data From the National Health Care Survey—This type of

report contains statistics on health resources and the public’s

use of health care resources including ambulatory, hospital,

and long-term care services based on data collected directly

from health care providers and provider records.

Series 20.	 Data on Mortality—This type of report contains statistics on

mortality that are not included in regular, annual, or monthly

reports. Special analyses by cause of death, age, other

demographic variables, and geographic and trend analyses

are included.

Series 21.	 Data on Natality, Marriage, and Divorce—This type of

report contains statistics on natality, marriage, and divorce

that are not included in regular, annual, or monthly reports.

Special analyses by health and demographic variables and

geographic and trend analyses are included.

Series 23.	 Data From the National Survey of Family Growth—These

reports contain statistics on factors that affect birth rates,

including contraception and infertility; factors affecting the

formation and dissolution of families, including cohabitation,

marriage, divorce, and remarriage; and behavior related to

the risk of HIV and other sexually transmitted diseases.

These statistics are based on national surveys of women and

men of childbearing age.

DISCONTINUED SERIES

Series 4.	 Documents and Committee Reports—These are final

reports of major committees concerned with vital and health

statistics and documents. The last Series 4 report was

published in 2002. As of 2009, this type of report is included

in Series 2 or another appropriate series, depending on the

report topic.

Series 5.	 International Vital and Health Statistics Reports—This

type of report compares U.S. vital and health statistics with

those of other countries or presents other international data of

relevance to the health statistics system of the United States.

The last Series 5 report was published in 2003. As of 2009,

this type of report is included in Series 3 or another series,

depending on the report topic.

Series 6.	 Cognition and Survey Measurement—This type of report

uses methods of cognitive science to design, evaluate, and

test survey instruments. The last Series 6 report was

published in 1999. As of 2009, this type of report is included

in Series 2.

Series 12.	 Data From the Institutionalized Population Surveys—

The last Series 12 report was published in 1974. Reports

from these surveys are included in Series 13.

Series 14.	 Data on Health Resources: Manpower and Facilities—

The last Series 14 report was published in 1989. Reports on

health resources are included in Series 13.

Series 15.	 Data From Special Surveys—This type of report contains

statistics on health and health-related topics collected in

special surveys that are not part of the continuing data

systems of the National Center for Health Statistics. The last

Series 15 report was published in 2002. As of 2009, reports

based on these surveys are included in Series 3.

Series 16.	 Compilations of Advance Data From Vital and Health

Statistics—The last Series 16 report was published in 1996.

All reports are available online, and so compilations of

Advance Data reports are no longer needed.

Series 22.	 Data From the National Mortality and Natality Surveys—

The last Series 22 report was published in 1973. Reports

from these sample surveys, based on vital records, are

published in Series 20 or 21.

Series 24.	 Compilations of Data on Natality, Mortality, Marriage, and

Divorce—The last Series 24 report was published in 1996.

All reports are available online, and so compilations of reports

are no longer needed.

For answers to questions about this report or for a list of reports published

in these series, contact:

Information Dissemination Staff
 

National Center for Health Statistics
 

Centers for Disease Control and Prevention
 

3311 Toledo Road, Room 5419
 

Hyattsville, MD 20782
 

Tel: 1–800–CDC–INFO (1–800–232–4636)
 

TTY: 1–888–232–6348
 

Internet: http://www.cdc.gov/nchs
 

Online request form: http://www.cdc.gov/cdc-info/
 

requestform.html

For e-mail updates on NCHS publication releases, subscribe

online at: http://www.cdc.gov/nchs/govdelivery.htm.
PRINTER: ADJUST THE SPINE TO FIT

HHS Publication No. 2013–1332, Series 1, No. 56S240459