Information Sheet

August 2008

National Health and Nutrition Examination Survey

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About NCHS     National Health and Nutrition Examination Survey
Diseases, medical conditions, health indicators studied    Why is NHANES unique?
Methods of data collection    Examples of NHANES Data    Challenges and Future Opportunities

About NCHS

The CDC's National Center for Health Statistics (NCHS) is the nation's principal health statistics agency, providing data to identify and address health issues. NCHS compiles statistical information to help guide public health and health policy decisions.

Collaborating with other public and private health partners, NCHS employs a variety of data collection mechanisms to obtain accurate information from multiple sources. This process provides a broad perspective to help us understand the populations' health, influences on health, and health outcomes.

National Health and Nutrition Examination Survey

The NHANES is NCHS' most in-depth and logistically complex survey, designed to assess the health and nutritional status of Americans. This comprehensive survey combines personal interviews with standardized physical examinations, diagnostic procedures, and lab tests on approximately 5,000 persons each year.

Diseases, medical conditions, health indicators studied

• Allergies
• Anemia
• Diabetes
• Eye diseases
• Hearing loss
• Kidney disease
• Nutrition
• Obesity
• Oral health
• Osteoporosis
• Physical activity and fitness
• Sexual behavior
• Vision
• Cardiovascular Disease
• Cognitive Functioning
• Environmental Exposure
• Infectious Diseases
• Reproductive History
• Sexually Transmitted Diseases
• Supplements and Medications

Why is NHANES unique?

• The survey results provide an objective assessment of health status through personal interviews, standardized physical exams, and laboratory tests.
• The results provide information on a broad range of health topics based on a variety of risk factors, and medical and personal information collected in the survey.
• Annually, a nationally representative sample of 5,000 individuals of all ages is examined. Persons currently over sampled include African Americans, Hispanics, and persons over age 60.
• The physical exams are conducted in Mobile Examination Centers that travel to 15 U.S. sites annually, allowing trained specialists to work in quality controlled settings.
• The data can be linked to Medicare and National Death Index records to permit studies of disease outcomes.
• The data produce national references for such measurements as height, weight, and blood pressure.
• NHANES serves as the data collection mechanism for a joint Health and Human Services/U.S. Department of Agriculture effort to monitor the diet and nutritional status of Americans, providing information needed for food policy and dietary guidelines.

Methods of data collection

• Home-based interviews
• Mobile Examination Centers
  • Physical medical exams
  • Standardized dental exams
  • Physiological measurements
  • Laboratory tests on blood and urine

Examples of NHANES Data

(1) significantly different from the non-Hispanic white population
(2) significantly different from the non-Hispanic white and Mexican- American population.
NOTE: obesity is defined as body mass index > 30
Source: National Health and Nutrition Examination Survey, 2005-2006.

• More than one-third of U.S. adults were obese in 2005-2006. This includes 33.3 percent of men and 35.3 percent of women.
• Obesity rates have increased since the 1976-1980 survey period. There was no significant change in obesity prevalence, however, between 2003-2004 and 2005-2006 for either men or women.
• Recent data show racial and ethnic obesity disparities for women but not for men. Non-Hispanic black and Mexican-American women were more likely to be obese than non-Hispanic white women.
• Among obese adults, approximately two-thirds have been told by a health care provider that they are overweight.

• Mean serum total cholesterol levels of U.S. adults aged 20 years and older declined from 204 mg/dL in 1999-2000 to 199 mg/dL in 2005-2006. The Healthy People 2010 objective to reduce mean serum cholesterol levels among adults to less than 200 mg/dL was met.
• Mean serum total cholesterol levels declined for men aged 40 years and older and for women aged 60 years and older over the time period 1999-2006. There was no significant change for men and women aged 20-39 years or for women aged 40-59 years.

Challenges and Future Opportunities

• Identify an ongoing, sustained funding base for NHANES field operations.
• Institute an ongoing program of research, development and testing of new measurement approaches for use in health examination surveys. As health issues and biomedical science advance, there is a continuing need to develop new components of NHANES and related surveys to ensure that needed information can be collected using state of the art methods.
• Meet data needs at the state and local levels through smaller scale, targeted examinations - "Community Health and Nutrition Examination Surveys." These surveys can provide important insights for state public health programs into the health status, risk factor, and environmental issues of communities.

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National Center for Health Statistics
3311 Toledo Road
Hyattsville, MD 20782
Phone:
1-800-232-4636
nchsquery@cdc.gov

Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 / Public Inquiries: (404) 639-3534 / (800) 311-3435