Figure 2.
The flow diagram of literature retrieval and selection. A total of 392 articles were captured by search strategy. After review, 7 studies were identified eligible for inclusion in this meta-analysis finally.
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.