Fig. 4.
Funnel plot for evaluating potential publication bias. Each solid circle represents a study in the meta-analysis. The line is the regression line
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.