NHANES III for older persons: nutrition content and methodological considerations.

The National Health and Nutrition Examination Surveys (NHANES) are important in the assessment of nutritional status of the population of the United States. The utility of these surveys for assessment of the nutritional status of older Americans has been limited because prior NHANES have not included persons aged greater than or equal to 75 y. This paper reviews the role of the NHANES for nutritional epidemiology, highlighting the unique opportunity NHANES III offers to expand the nutrition database for older persons. Data are presented on consequences of nonresponse in analytic work and mechanisms that have been devised to approach the potential problem of nonresponse within NHANES III.