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.
Squares indicate estimates, with the size of the squares corresponding to weight. Horizontal lines represent 95% CIs. Diamonds indicate pooled estimates, with points indicating 95% CIs. OR indicates odds ratio.
