National Health and Nutrition Examination Survey (NHANES) and Followup Series

Investigator(s): National Center for Health Statistics

The National Health and Nutrition Examination Survey (NHANES) is a program of studies designed to assess the health and nutritional status of adults and children in the United States. The survey combines interviews and physical examinations. NHANES is a major program of the National Center for Health Statistics (NCHS); NCHS is part of the Centers for Disease Control and Prevention (CDC).

The NHANES series archived with ICPSR and NACDA includes:

  • Continuous NHANES data (1999 and later)
  • Historical NHANES I, II, III
  • Hispanic HANES
  • NHANES I Epidemiologic Followup Survey (NHEFS)

The NHANES I and NHANES II datasets were formerly titled HEALTH AND NUTRITION EXAMINATION SURVEYS by ICPSR. This series succeeds the National Center for Health Statistics' NATIONAL HEALTH EXAMINATION SURVEY (NHES) series, which was collected from 1959 to 1970.

All of the NHANES datasets use complex, multistage, stratified, clustered samples of civilian non-institutionalized populations. All of the files within each study are linkable to each other.

The NHANES I (1971-1975) interviewed a sample of 31,973 persons aged 1-74 years. The sample was selected so that certain population groups thought to be at high risk of malnutrition (persons with low incomes, preschool children, women of childbearing age, and the elderly) were oversampled at preset rates. On completion of the survey, 23,808 of the interviewed sample were given a medical examination, and this information is also part of the NHANES I data collections.

The second National Health and Nutrition Examination Survey, NHANES II (1976-1980), was designed to continue the measurement and monitoring of the nutritional status and health of the United States population. From the sample of 27,801 persons aged 6 months to 74 years, 25,286 people were interviewed and 20,322 were both interviewed and examined. Because children and persons classified as living at or below the poverty level were assumed to be at special risk of having nutritional problems, they were sampled at rates substantially higher than their proportions in the general population.

The NHANES III (1988-1994) contains information on a sample of 33,994 persons aged 2 months and older. A home examination was employed for the first time in order to obtain examination data for very young children and for the elderly.

The NHANES I Epidemiologic Followup Study (NHEFS) is a longitudinal study designed to investigate the relationships between clinical, nutritional, and behavioral factors assessed in NHANES I and subsequent morbidity, mortality, and hospital utilization, as well as changes in risk factors, functional limitation, and institutionalization. The NHEFS cohort includes all persons aged 25-74 who completed a medical examination for NHANES I (N = 14,407).

The Hispanic HANES (HHANES) was conducted to obtain sufficient numbers to produce estimates of the health and nutritional status of Hispanics in general, as well as specific data for Puerto Ricans, Mexican Americans, and Cuban Americans. Included in the survey are Mexican Americans from Texas, Colorado, New Mexico, Arizona, and California (N = 7,462), Cuban Americans from Dade County, Florida (N = 1,357), and Puerto Ricans from the New York area, including parts of New Jersey and Connecticut (N = 2,834).

Limited access NHANES data are available through the CDC Restricted Data Center (RDC).

Recent years of data from this series can be found by visiting the Centers for Disease Control and Prevention's (CDC) project website and will not be curated by ICPSR and NACDA to avoid duplicate efforts and distribution.