DOI: 10.3886/e154401
title: National Health Interview Survey (NHIS) for Dementia Researchers, 2007-2018

description: This series of code and corresponding data files are intended for use in cognitive decline and Alzheimer’s disease and related dementias (ADRD) research. The files include twelve years of cleaned datasets derived from the 2007-2018 years of the National Health Interview Survey (NHIS). NHIS is a nationally representative study aimed at monitoring the health of the non-institutionalized United States population. <br> <br>The provided datasets include sociodemographic information on respondents’ age, sex, race, and marital status from the Sample Adult Files, cognition variables from the Sample Adult files and, in applicable years, merged cognition data from the Adult Functioning and Disability (AFD) supplement. The files were constructed to allow for users to append multiple years of data for longitudinal analysis. Brief and detailed summaries of the variables available in these datasets along with more detailed descriptions of performed calculations can be found in the provided data dictionaries. Users may also refer to the provided “Overview of variables across years” document to see which variables are available each year. SAS, Stata, and CSV data file formats are provided as are the full coding scripts used in Stata.<br>
description: Users of this resource should be familiar with complex survey design and appropriately apply the sample weights, strata, and cluster/primary sampling unit for any analyses. For years 2007-2010 weights from the sample adult file (wtfa_sa) should be used<b>. </b>For years 2011-2017, any analysis using the Adult Functioning and Disability (AFD) supplement should use the AFD weights (wtfa_afd). In 2018, the AFD was asked as part of the sample adult file, meaning users should apply the sample adult weights (wtfa_sa). For all years, Strata should be set to pseudo-stratum (strat_p) and cluster/PSU should be set to pseudo-PSU (psu_p). Please see the supplemental documentation on “Overview of Variables Across Years” for changes in stratum and PSU.<br><br>Users should consult the "NHIS Guidance on Variance Estimation" document in the Documentation folder for sample code, instructions on weight adjustments in pooled analyses, and instructions for handling the PSU/Stratum coding change from 2015 to 2016.
description: Complex survey data with a stratified, clustered sampling design.
description: Nationally representative sample of noninstitutionalized U.S. Adults. <br>IMPORTANT NOTE: NHIS does not sample from persons in long-term care institutions (e.g., nursing homes). Smallest Geographic Unit: U.S.A.
description: computer-assisted personal interview (CAPI); computer-assisted telephone interview (CATI); Senility questions, which are available in all years, were asked of Sample adults aged 18+ years who, without using special equipment, have at least a little difficulty walking a quarter mile; walking up 10 steps w/o resting; standing/being on feet for about 2 hours; sitting for about 2 hours; stooping/bending/kneeling; reaching up over head; using fingers to grasp/handle small objects; lifting/carrying 10 pounds; pushing/pulling large objects; going out for things (shopping/movies/etc.); participating in social activities; or relaxing at home (reading/sewing, etc.)