FIGURE 2.
Risk-of-bias graph and summary. (A) Overall risk of bias, with each category presented as percentages. (B) Risk of bias of the studies included in the systematic review.
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.