Figure 3.
Publication bias of the included studies. (A) Funnel plot for publication bias. (B) Egger’s test results. RR, relative risk; s.e., standard error.
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.