Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
a Wave I participants not included in the current analysis because it used self-reported height and weight data.
b Cases added in the field, selected as part of a paired subsample, or without a sample flag.
