Regional variations in Helicobacter pylori infection, gastric atrophy and gastric cancer risk: The ENIGMA study in Chile.

International audience; Background: Regional variations in gastric cancer incidence are not explained by prevalence of Helicobacter pylori, the main cause of the disease, with several areas presenting high H. pylori prevalence but low gastric cancer incidence. The IARC worldwide H. pylori prevalence surveys (ENIGMA) aim at systematically describing age and sex-specific prevalence of H. pylori infection around the world and generating hypotheses to explain regional variations in gastric cancer risk.Methods: We selected age- and sex-stratified population samples in two areas with different gastric cancer incidence and mortality in Chile: Antofagasta (lower rate) and Valdivia (higher rate). Pa…