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NHANES I (1971-1974)



The first National Health and Nutrition Examination Survey (NHANES I) was conducted on a nationwide probability sample of approximately 32,000 persons 1-74 years of age. The NHANES I 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, 31,973 sample persons had been interviewed; of these, 23,808 people were examined. Adjusted sampling weights were computed within 60 age-sex-race categories in order to inflate the sample so as to closely reflect the U.S. civilian noninstitutionalized population 1-74 years of age at the midpoint of the survey. Although a major emphasis of NHANES I was on nutrition and some limited aspects of health, a subset of 3,854 persons 25-74 years of age received a more detailed health examination. No oversampling of subgroups of the population was done in this subsample, as it had been for the major nutrition component. This subsample is representative of the U.S. population 25-74 years of age at the midpoint of NHANES I. After the nutrition survey was completed, the detailed medical examination was given to an additional sample of 3,059 adults 25-74 years of age. This portion of the survey is referred to as the NHANES I Augmentation and was continued through October 1975, bringing the total number of persons who received a detailed medical examination to 6,913.

Data from NHANES I are organized by subject matter. The data files comprising NHANES I include a number of demographic and socioeconomic variables on each tape, including age, gender, race, ethnicity, income, education, and marital status.


Contents in Detail


Using the Data


Data and Documentation/Codebook Files

README - NHANES I Dataset [PDF - 11 KB]