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.
Risk of bias for observational studies.
| Selection | Comparability | Outcome | Assessment | |
|---|---|---|---|---|
| Campo et al. (2014) | HIGH (2 pts) | HIGH (1 pt) | LOW (3 pts) | Poor |
| Cucinella et al. (2013) | HIGH (2 pts) | LOW (2 pts) | LOW (3 pts) | Fair |
| Dobrokhotova et al. (2017) | HIGH (2 pts) | LOW (2 pts) | LOW (3 pts) | Fair |
| Vercellini et al. (2008) | LOW (4 pts) | LOW (2 pts) | LOW (3 pts) | Good |
