NHEFS is a large sample that was representative of the US at the study's initiation in
1971-75. Over 14,000 persons participated in different segments of the research. We
studied only respondents who gave self-ratings of health at baseline, N=6913. Initial
response rates were very high and attrition during the follow-up period was very low.
Respondents were re-interviewed in 1982, 1987, and 1992. Our analysis takes the sample
design and weighting into account.
reports on the NHANES and NHEFS