Table 2.
Methodological quality of studies included in the final analysis based on the Newcastle–Ottawa Scale for assessing the quality of (a) case–control studies; (b) cohort studies.
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.