# Presentation: 442318

## Persistent Bioaccumulative Toxicants Workshop

- Larry L. Needham, PhD
- National Center for Environmental Health
- Centers for Disease Control and Prevention
- April 22, 2002

## Mission of Division of Laboratory Sciences

- To develop and apply analytical methods for
- assessing human exposure to environmental
- chemicals (and ultimately to be a team member for
- preventing / reducing morbidity and/or mortality in the
- US population.

## Mission statement (cont.)

- To address this mission, we collaborate with investigators within CDC, other federal agencies, state health departments, international agencies, academia, and industry.
- One of needs is to acquire background levels of environmental chemicals in human populations.

## National Report on Human Exposure

- to Environmental Chemicals

- Division of Laboratory Sciences,
- National Center for Environmental Health,
- CDC

## Organization for NHANES

**DHHS**

**FDA**

**CDC**

**NIH**

**NCID**

**NC**
**CDPHP**

**NCHS**

**NC**
**HIV,STD,**
**&TB**

**NIOSH**

**NCIPC**

**NCEH**

## Slide 6

## 23 Participating Laboratories for NHANES

- NHANES MEC
- Division of Laboratory Sciences / NCEH
- NCID labs
- NCHSTP

- Medical Research Centers/ Academic labs
- Commercial labs

## Eligible NHANES Population

- Civilian, non-institutionalized population of the United States
- Ages 2 months and older
- Residents of all 50 states and DC
- 5000 persons examined each year in 15 locations
- Survey design determines which populations are over-sampled

## How did NHANES start?

- The Health Examination Survey – the forerunner in the 1960’s
- HANES I – 1971; Nutrition added as a major component

## Six Principal Data Collection Methods

- Household interview
- Personal interviews
- Physical examination
- Anthropometry
- Diagnostic screening
- Laboratory analysis

## The Mobile Examination Centers (MECs)

## The Mobile Examination Centers (MECs)

- 4 Trailers attached to one another, each ~ 8’x45’
- 3 Sets: 2 in operation at any given time
- 15 sites visited each year, 4-6 wk/location
- Survey design: Northern U.S. states in summer, Southern states in winter
- Average of 450 sample persons per survey location
- Provides standardized environment
- 20 Examinations per day in two sessions per day, (morning/afternoon or morning/evening), Wed-Sun

## MEC examination components

- Dietary interviews/MEC interviews
- Phlebotomy
- Urine collection
- Blood pressure
- Physician’s exam
- Hearing
- Eye exam
- Dental exam
- DXA

- Muscle strength
- Balance
- Anthropometry
- Skin disease/Melanoma
- TB skin test
- Cognitive testing
- Cardiorespiratory fitness
- Peripheral vascular disease
- Peripheral neuropathy

## NHANES Laboratory in the MEC

- Coulter
- Counter for CBC

- Laminar
- Flow Hood

## CDCNCHSMEC

- CDC CASPIR

- CDC NCEH DLS

## What Purpose Does NHANES Serve?

- Serves as a warning system for health problems

## Urinary Iodine levels

- Monitoring of iodine levels through NHANES can provide a warning of thyroid deficiency trends
- Studies show that median iodine levels in the population are dropping due to decreased food iodization from salt
- Health problems could occur if trend continues

## What Purpose Does NHANES Serve?

- Helps identify who is at risk.

## Distribution of serum cotinine in the U.S. Population

**(ages 4 and older), NHANES III (1988-1991)**

## Serum Cotinine Levels in the U.S. Population by Self-reported Exposure to Tobacco Smoke, NHANES III (1988-1991)

**Percentage of the Population**

**Serum Cotinine Levels in the U.S. Population by Self-reported Exposure to Tobacco Smoke, NHANES III (1988-1991)**

## What Purpose Does NHANES Serve?

- Shows if public health interventions have been successful through trend data.

## Lead used in gasoline declined from 1976 through 1980

- 1975

- 1976

- 1977

- 1978

- 1979

- 1980

- 1981

- Lead used in gasoline (thousands of tons)

- 30

- 40

- 50

- 60

- 70

- 80

- 90

- 100

- 110

- Gasoline lead

**Lead used in gasoline declined from 1976 through 1980**

## Environmental Modeling Predicted Only a Slight Decline in Blood Lead Levels in People

- 1975

- 1976

- 1977

- 1978

- 1979

- 1980

- 1981

- 30

- 40

- 50

- 60

- 70

- 80

- 90

- 100

- 110

- Mean blood
- lead levels
- (ug/dL)

- 9

- 10

- 11

- 12

- 13

- 14

- 15

- 16

- 17

- Gasoline lead

- Predicted blood lead

- Lead used in gasoline (thousands of tons)

**Environmental Modeling Predicted Only a Slight Decline in Blood Lead Levels in People**

## NHANES II Blood Lead Measurements Found a Substantial Decline in Blood Lead Levels, 10 Times More Than Predicted From Environmental Modeling

- Year

- 1975

- 1976

- 1977

- 1978

- 1979

- 1980

- 1981

- 30

- 40

- 50

- 60

- 70

- 80

- 90

- 100

- 110

- 9

- 10

- 11

- 12

- 13

- 14

- 15

- 16

- 17

- Gasoline lead

- Predicted blood lead

- Lead used in gasoline (thousands of tons)

- Mean blood
- lead levels
- (ug/dL)

**NHANES II Blood Lead Measurements Found a Substantial Decline in Blood Lead Levels, 10 Times More Than Predicted From Environmental Modeling**

## NHANES III (1988-1991) Blood Lead Measurements Showed That After NHANES II (1976-1980), Blood Lead Levels Continued to Decrease As Gasoline Levels Declined

- 1974

- 1976

- 1978

- 1980

- 1982

- 1984

- 1986

- 1988

- 1990

- 1992

- 0

- 20

- 40

- 60

- 80

- 100

- 2

- 4

- 6

- 8

- 10

- 12

- 14

- 16

- 18

- Blood lead

- Gasoline lead

- Lead used in gasoline (thousands of tons)

- Mean blood
- lead levels
- (ug/dL)

- NHANES III (1988-1991) Blood Lead Measurements Showed That After NHANES II (1976-1980), Blood Lead Levels Continued to Decrease As Gasoline Levels Declined

## Blood lead levels in NHANES surveys: children 1- 5 years

**0 **

**20 **

**40 **

**60 **

**80 **

**100 **

- Percent of children
- with blood lead
- levels <10 ug/dL

- 1976-80
- NHANES II

- 1988-91
- NHANES III

**88.2**

**8.9**

**Blood lead levels in NHANES surveys: children 1- 5 years**

## How was it proven that the declining blood lead levels were due to changes in the environment, and not due to analytical errors?

MEASUREMENT OF LONG-TERM, 
STABLE QUALITY CONTROL MATERIALS
CALIBRATED AGAINST NIST SRMs

- MEASUREMENT OF LONG-TERM,
- STABLE QUALITY CONTROL MATERIALS
- CALIBRATED AGAINST NIST SRMs

## What purpose does NHANES serve?

- In toxicology studies – helps prioritize.

## Methyl Eugenol

- Occurs naturally in clove oil, nutmeg, allspice, walnuts
- Uses: Flavoring agent, insect attractant, fragrance (30,000 kg/yr)
- Consumption Rate: 6 g/day

## DLS’ Commitment to Analyses for NHANES Has Increased With Each Successive Survey

- 1971-1975  HANES I - 20,000 subjects
- NHANES Central Laboratory established
- Strictly nutrition-oriented survey
- 22 Analytes measured, all at CDC
- Hematology a primary component; CBC done in MEC
- Abell-Kendall reference cholesterol method used
- 1976-1980  HANES II - 20,000 subjects
- Six outside labs are added
- 21 analytes measured; blind QC added
- Trace metals added (Pb, Zn, Cu)
- Hepatitis  and STD prevalence first assessed
- EPA assessed human exposure to OC and OP pesticides and phenols.

## DLS’ commitment to analyses for NHANES has increased with each successive survey

- 1982-1984 Hispanic HANES - 12,000 subjects
- Mexican-American, Cuban, Puerto-Rican subjects
- Four outside labs
- 37 Analytes measured, HPLC debuts
- Hair collection for trace metals added
- EPA assessed human exposure to OC and OP pesticides and phenols.

## DLS’ commitment to analyses for NHANES has increased with each successive survey

- 1988-1994  NHANES III - 30,000 subjects
- 12 contract labs
- First survey to use bar codes
- 85+ Analytes; cotinine is major component
- Lab manual is >700 pages and is published on CD-ROM)
- RBase used for survey database; still using mainframe
- LN2 storage introduced for reserve serum aliquots
- Selenium, Genetics component added
- Subset for VOCs and pesticide metabolites.

## National Report on Human Exposure

- to Environmental Chemicals

- Division of Laboratory Sciences,
- National Center for Environmental Health,
- CDC

## National Report on Human Exposure to Environmental Chemicals - 1999

| Matrix | Age Range | N | Assessment |
| --- | --- | --- | --- |
| Blood |  1 year | 3,189 | Pb, Cd |
| Blood | 1-5 years | 248 | Hg |
| Blood | 16-49 years (F) | 679 | Hg |
| Urine |  6 years | ~1000 | Sb, BA, Be, Cd, Ce, Co, Pb, Mb, Pt, Th, W, U |
| Urine |  6 years | ~1000 | OPs (6), Phthalates (7) |
| Serum |  3 years | 2263 | cotinine |

## National Report on Human Exposure to Environmental Chemicals –1999/2000

| Matrix | Age Range | N | Assessment |
| --- | --- | --- | --- |
| Blood |  1 year |  | Pb, Cd |
| Blood | 1-5 years |  | Hg |
| Blood | 16-49 years (F) |  | Hg |
| Blood |  12 years |  | VOCs |
| Serum |  3 years |  | cotinine |
| Serum |  12 years |  | PCBs (38), PCDDs (7), PCDFs (10), coplanar PCBs (4) , OC insecticides (10) |
| Serum |  12 years |  | Se |
| Urine |  6 years |  | Sb, Ba, Be, Cd, Ce, Co, Pb, Mb, Pt, Th, W, U, Hg |
| Urine |  6 years |  | OPs (6), Phthalates (7), PAHs (18), Phytoestrogens (8), additional NPPs |

- Does the test have biological relevance?
- Is there a correlation between the biomarker and dietary intake or exposure data?
- Does the condition occur frequently enough in the population?
- Is there a validated method available?
- Can we afford the cost of the assay?
- Is there financial support for the assay?

- Primary Criteria for Consideration for Inclusion of Analytes in NHANES

## Exposure Pathway (Partial) for Toxicant

**Exposure Pathway (Partial) for Toxicant**

**Source**

- Environmental Fate
- and Transport

- Exposure

- Absorption Barriers

*Air, Water, Food, Soil, Surfaces*

*GI tract wall*

*Lung tissue*

*Skin*

- Internal Dose

- Biological Effective Dose

## Life Cycle

**Life Cycle**

**Conception**

- Birth

- Death

- 1 y

- 2 y

- 3 y

- 6 y

- 12 y

- 18-21 y

*Infancy*

*Young toddler*

*Older toddler*

*Preschool*

*Pre High School*

*Adolescence*

*Trimesters*

*Embryonic (8d – 8w)*