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 vertical line, “no difference” point between the two groups; horizontal line, 95% confidence interval; squares, risk ratios; diamonds, pooled risk ratios.
CI, confidence interval; MH, Mantel-Haenszel.
