NCHS Data Brief ■ No. 66 ■ July 2011

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Use of the Internet for Health Information: United States, 2009

Robin A. Cohen, Ph.D.; and Patricia F. Adams

Key findings

Data from the National 

Health Interview Survey, 

2009

•	 Among adults aged 18 and

over, women were more likely

than men to have used the

Internet for health information.

•	 Among adults aged 18–64,

non-Hispanic white persons

were almost twice as likely

as Hispanic persons to have

used the Internet for health

information.

•	 Adults aged 18–64 with

higher incomes were more

likely to have used the Internet

for health information than

adults with lower incomes.

•	 Employed adults aged 18–64

were more likely than adults

who were unemployed or not in

the workforce to have used the

Internet for health information. 

Research has shown that 74% of all U.S. adults use the Internet, and 61% have

looked for health or medical information on the Internet (1). Additionally, 49%

have accessed a website that provides information about a specific medical

condition or problem. In 2009, the National Health Interview Survey (NHIS)

became the first nationally representative household survey to collect data on

the use of health information technology when the U.S. Department of Health

and Human Services, Office of the Assistant Secretary for Planning and

Evaluation sponsored 10 questions that asked about use of the Internet to look

up health information, refill a prescription, schedule a medical appointment,

learn about health topics in online chat groups, and e-mail a health care

provider. This report provides estimates, using 2009 NHIS data, about adult

use of the Internet for health information in the past 12 months, by selected

sociodemographic characteristics.

Keywords: health information technology, Internet, National Health Interview 

Survey

Among adults aged 18 and over, women were more likely 

than men to have used the Internet for health information. 













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NCHS Data Brief ■ No. 66 ■ July 2011

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Women were more likely than men to have used the Internet for health information in the past 12

months for each age group except 65 and over (Figure 1).

The percentage of adults who used the Internet for health information was highest among women

aged 25–34 (65.8%) and lowest among adults aged 65 and over (under 25%).

Among adults aged 18–64, non-Hispanic white persons were almost 

twice as likely as Hispanic persons to have used the Internet for health 

information.

Use of the Internet by adults aged 18–64 for health information in the past 12 months was highest

for adults who were non-Hispanic white (57.3%), followed by non-Hispanic Asian (47.8%), nonHispanic black (38.3%), and Hispanic (28.8%) (Figure 2).

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NCHS Data Brief ■ No. 66 ■ July 2011

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Among adults aged 25–64, higher education was associated with increased 

use of the Internet for health information.

Among adults aged 25–64, 73.8% of persons with at least a college degree used the Internet for

health information in the past 12 months, while only 13.8% of those with less than a high school

education did so (Figure 3).



 















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Adults aged 18–64 with higher incomes were more likely to have used the 

Internet for health information than adults with lower incomes.

Adults aged 18–64 with incomes at or above 300% of the federal poverty level (FPL) were more

than twice as likely (63.4%) to have used the Internet for health information in the past 12 months

compared with adults with incomes less than 100% of the FPL (28.9%) (Figure 4).

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NCHS Data Brief ■ No. 66 ■ July 2011

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Employed adults aged 18–64 were more likely than adults who were 

unemployed or not in the workforce to have used the Internet for health 

information. 

More than one-half (53.4%) of employed adults aged 18–64 used the Internet for health

information in the past 12 months compared with 40.9% of unemployed adults and 42.5% of

adults not in the workforce (Figure 5).

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Using the Internet for health information was related to health insurance 

status.

Among adults aged 18–64, 58.7% of those with private health insurance coverage used the

Internet for health information in the past 12 months compared with 31.3% of those on Medicaid

and 33.3% of those with no insurance coverage (Figure 6).

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NCHS Data Brief ■ No. 66 ■ July 2011

■  5  ■

Summary 

Sociodemographic and socioeconomic factors were associated with adults who had used the

Internet to look up health information. Greater use of the Internet for health information in

the past 12 months among adults was associated with being ages 25–44, non-Hispanic white,

employed, college educated, with income at or above 300% of the FPL, and having private health

insurance.

The active involvement of consumers in managing their health care includes activities such as

use of computers to access, retrieve, store, or share health care information. For consumers this

may include using the Internet to look up health information, using e-mail or text messaging to

communicate with health care providers or pharmacies, and having an electronic health record.

As the percentage of adults in the United States using the Internet continues to grow, the Internet

as a source of health information for consumers may become increasingly important. Although

use of the Internet has the potential to improve consumer health by facilitating communication

between providers and patients and among providers, previous research has found that many

consumers are concerned about security and confidentiality issues related to scheduling medical

appointments or accessing personal health records online (2).

Definitions 

Looked up health information on the Internet in the past 12 months: Based on a positive response

to both of the following questions: “Have you ever used computers for any of the following? ...

Looked up health information on the Internet” and “Did you look up health information on the

Internet in the past 12 months?” Adults who answered “Refused” or “Don’t know” for either of

these questions were excluded from the denominator for this analysis.

Poverty status and percentage of poverty level: Based on family income, family size, and the

number of children in the family, and, for families with two or fewer adults, on the age of the

adults in the family. The poverty level is based on definitions originally developed by the Social

Security Administration. These include a set of income thresholds defining the FPL that vary

by family size and composition. Families or individuals with incomes below their appropriate

thresholds are classified as below the poverty level. These thresholds are updated annually by the

U.S. Census Bureau to reflect changes in the Consumer Price Index for all urban consumers. For

further information, visit http://www.census.gov/hhes/www/poverty/poverty.html. Estimates by

poverty status are based on both reported and imputed family income. Family income information

was completely missing for 5% of persons, and was only reported in broad categories for an

additional 19% of persons in 2009. Therefore, family income was imputed for 24% of persons in

2009 using NHIS imputed income files (3). Note that NHIS asks respondents about their personal

earnings and family income for the previous calendar year; therefore, U.S. Census Bureau

poverty thresholds for the previous calendar year should be used when calculating poverty ratios

for the current NHIS survey year. For example, the poverty ratios in the 2009 NHIS data files

were calculated using the U.S. Census Bureau’s 2008 poverty thresholds (4).

Health insurance coverage: Defined broadly to include both public and private payers who cover

medical expenditures incurred by a defined population in a variety of settings. This includes

persons covered by private health insurance, whether offered through employment or purchased

individually, and persons covered by public programs such as Medicare, Medicaid, Children’s
NCHS Data Brief ■ No. 66 ■ July 2011

■  6  ■

Health Insurance Program (CHIP), and other state-sponsored programs. Persons with only Indian

Health Service (IHS) coverage or having only a private plan that paid for one type of service such

as accidents or dental care were not considered to be covered by health insurance. In this report,

coverage is measured only on the day of the NHIS interview.

Private insurance: Indicated when respondents report that they were covered by private health

insurance through an employer, union, or individual purchase. Private health insurance includes

managed care such as health maintenance organizations and does not include military health

plans.

Medicaid: Indicated when respondents report that they were covered by Medicaid. Individuals

were also considered covered by Medicaid if they reported coverage by CHIP or other statesponsored plans. In this analysis, health insurance categories are hierarchical, and adults covered

by both private insurance and Medicaid were considered to have private insurance.

Other coverage: Includes persons who do not have private coverage or Medicaid (or other public

coverage), but who have any type of military health plan (includes VA, TRICARE, and CHAMP–

VA) or Medicare. This category also includes persons who are covered by other government

programs.

Uninsured: Indicated when respondents report that they did not have coverage under private

health insurance, Medicare, Medicaid, CHIP, another state-sponsored health plan, other

government-sponsored programs, or a military health plan (TRICARE, VA, or CHAMP–VA).

A person was also defined as uninsured if he or she had only IHS coverage or a private plan that

paid for one type of service such as accidents or dental care.

Data source and methods

Data from the 2009 NHIS were used for this analysis. NHIS is conducted continuously

throughout the year by interviewers of the U.S. Census Bureau for the Centers for Disease

Control and Prevention’s (CDC) National Center for Health Statistics (NCHS). NHIS collects

information about the health and health care of the civilian noninstitutionalized U.S. population.

Interviews are conducted in respondents’ homes, but followups to complete interviews may

be conducted over the telephone. In the Family component of the survey, family respondents

are asked questions about everyone in the family, including questions about health insurance

coverage. Questions on use of the Internet are from the Sample Adult component. In 2009,

information was collected on a total of 27,731 persons aged 18 and over from the Sample Adult

component of the survey. For further information about NHIS, including the questionnaire, visit

http://www.cdc.gov/nchs/nhis.htm.

NHIS is designed to yield a sample representative of the civilian noninstitutionalized population

of the United States, and this analysis uses weights to produce national estimates. Dataweighting procedures are described in more detail elsewhere (5). Point estimates and estimates

of corresponding variances for this analysis were calculated using SUDAAN software (6) to

account for the complex sample design of NHIS. The Taylor series linearization method was

chosen for variance estimation. Differences between percentages were evaluated using twosided significance tests at the 0.05 level. Terms such as “higher than” and “less than” indicate

statistically significant differences. Terms such as “similar” and “no difference” indicate that
NCHS Data Brief ■ No. 66 ■ July 2011

■  7  ■

the	statistics	being	compared	were	not	significantly	different.	Lack	of	comment	regarding	the	

difference	between	any	two	statistics	does	not	necessarily	suggest	that	the	difference	was	tested	

and	found	to	be	not	significant.	

About the authors

Robin	A.	Cohen	and	Patricia	F.	Adams	are	with	CDC’s	NCHS,	Division	of	Health	Interview	

Statistics.

References

1.	 Fox	S,	Jones	S.	The	social	life	of	Internet	users.	Washington,	DC:	Pew	Internet	&	American	

Life	Project.	2009.

2.	 The	state	of	health	information	technology	in	California.	Oakland,	CA:	California	HealthCare	

Foundation.	2008.

3.	 Schenker	N,	Raghunathan	TE,	Chiu	PL,	et	al.	Multiple	imputation	of	family	income	and	

personal	earnings	in	the	National	Health	Interview	Survey:	Methods	and	examples.	Available	

from:	http://www.cdc.gov/nchs/data/nhis/tecdoc.pdf.

4.	 DeNavas-Walt	C,	Proctor	BD,	Smith	JC.	Income,	poverty,	and	health	insurance	coverage	in	

the	United	States:	2008.	U.S.	Census	Bureau.	Current	population	reports,	P60–236.	Washington,	

DC:	U.S.	Government	Printing	Office.	2009.	Available	from:	http://www.census.gov/

prod/2009pubs/p60-236.pdf.

5.	 Botman	SL,	Moore	TF,	Moriarity	CL,	Parsons	VL.	Design	and	estimation	for	the	National	

Health	Interview	Survey,	1995–2004.	National	Center	for	Health	Statistics.	Vital	Health	Stat	

2(130).	2000.

6.	 Research	Triangle	Institute.	SUDAAN	(Release	10.0).	Research	Triangle	Park,	NC:	Research	

Triangle	Institute.	2008.	
NCHS Data Brief ■ No. 66 ■ July 2011

Suggested citation

Cohen RA, Adams PF. Use of the Internet

for health information: United States, 2009.

NCHS data brief, no 66. Hyattsville, MD:

National Center for Health Statistics. 2011.

Copyright Information 

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the public domain and may be reproduced

or copied without permission; citation as to

source, however, is appreciated.

National Center for Health 

Statistics

Edward J. Sondik, Ph.D., Director

Jennifer H. Madans, Ph.D., Associate 

Director for Science

Division of Health Interview Statistics

Jane F. Gentleman, Ph.D., Director

U.S. DEPARTMENT OF

HEALTH & HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

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