Figure 2.
Methodological quality of included articles using the Newcastle–Ottawa Quality Assessment Scale. Yes: +; no: -; cannot say: ?; not applicable: NA.
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.