Figure 1. Demographic characteristics of individuals collected in the sample.
A) The altitude distribution of subjects' native place; B) The smoking status of individuals; C) The drinking status of the individuals.
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.