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. An ongoing annual survey combines interviews and physical examinations. The NHANES interview includes demographic, socioeconomic, dietary, and health-related questions. The examination component consists of medical, dental, and physiological measurements, as well as laboratory tests administered by highly trained medical personnel.

Ancillary studies include the NHANES National Youth Fitness Survey (NNYFS) and NHANES Epidemiologic Followup Study (NHEFS). NNYFS was conducted in 2012 to evaluate the physical activity and fitness of children aged 3 to 15 years old through interviews and fitness tests. NHEFS is a longitudinal survey of adults aged 25 to 74 years old in the NHANES I (1971-1975) cohort who completed a medical examination. Data was collected in follow-up rounds in 1982-1984, 1986, 1987, and 1992 through subject and proxy interviews and vital record search. Available data files include vital and tracing status, demographic information, interview data on health status, health care facility inpatient data, and mortality data.