The National Health and Nutrition Examination Survey (NHANES) describes the prevalent health conditions, health behaviors, nutrition, and environmental exposures in a sample representative of the US non-institutionalized population of the US [4
]. Data sources are derived from an annual survey of approximately 5,000 participants of all ages with oversampling of blacks and Hispanics and those over 60 years of age. Data include household interviews, physical examinations, laboratory tests, nutritional assessment, and DNA repository.
Specific data collected that could be applicable to the study of liver disease include the following: body mass index, medications within the past 30 days, over-the-counter medications, diet, physical examination [liver ultrasound performed during the Hispanic HANES (HHANES) in 1982], laboratory data including hepatitis A, hepatitis B sAg, sAb, cAb, hepatitis C and RIBA, hepatitis D, tests of liver injury and function (excluding INR), chemistries, iron studies, HIV status, and C-reactive protein. Other laboratory data and urinalysis exist to measure environmental and toxic exposures. Several liver-related interview questions include the presence of any liver disease, age at time of disease, liver cancer, receipt of hepatitis vaccinations, alcohol use and history, illicit drug use, and sexual behavior. Note that extra DNA, serum, and plasma have been archived, and research proposals are necessary to access them. The strength of NHANES is that it provides a snapshot of the population health, and thus has been used in several studies of liver disease [4
]. The lack of longitudinal data except for vital statistics and the relatively small sample size (~5,000) are limitations to the use of this database.
Opportunities exist to petition question items for future surveys and laboratory or imaging tests as well as collaborative ancillary investigations. Upcoming laboratory data that will be collected include celiac antibody testing (IgA-tissue transglutaminase, IgA-endomysial antibody), HLA-B27, and detailed lipid profile in 2009–2010. These descriptions are not meant to be inclusive of all liver-related data available through NHANES.