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.
Abbreviations: CI, confidence interval; M-H, Mantel-Haenszel.
Sources: Data from Fracalanza et al, 2008,42 Ham et al, 2008,44 Ficarra et al, 2009,40 Doumerc et al, 2010,38 Di Pierro et al, 2011,37 Kim et al, 2011,46 Philippou et al, 2012.54
