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.
Pooled ORs for the relationship between H. pylori infection of the gallbladder and chronic cholecystitis and cholelithiasis: (a) subgroup based on country; (b) subgroup based on sample; (c) subgroup based on specific primer. The areas of the squares are proportional to the study sample sizes.
