Smoking Behavior and Risk of Helicobacter Pylori Infection,Gastric Atrophy and Gastric Cancer in Japanese

Although many studies have shown that smoking is an established risk factor for gastric cancer, relativelyfew studies have investigated on which step smoking has effects in Helicobacter pylori (H. pylori) related gastriccarcinogenesis. In this study we investigated the association of smoking with risk of three steps leading to gastriccancer: H. pylori infection, gastric atrophy, and gastric cancer. Among the participants who visited Aichi CancerCenter Hospital from year 2001 to 2005, 583 cases diagnosed as gastric cancer and age-and sex-frequency-matched1,742 cancer free controls were sampled, from whom those without serum samples or without information aboutsmoking habit were excluded, leaving 576 cases and 1,599 controls eligible for the analyses. Anti- H. pylori IgGantibody and serum pepsinogens (PG) were measured to detect H. pylori infection and gastric atrophy. Smokingstatus was asked by a self-administered questionnaire. The odds ratio (OR) of H. pylori infection, as well as theOR of gastric atrophy among the H. pylori seropositive controls was not significant for smokers. The age- andsex-adjusted OR of gastric cancer was significantly elevated relative to the subjects with gastric atrophy: OR=1.62(95% confidence interval (CI), 1.19-2.22; P=0.002) for ever smokers and 2.52 (1.75-3.64; P<0.001) for currentsmokers, relative to never smokers. This study revealed that smoking behavior contributed to the increased riskof gastric carcinogenesis from gastric atrophy, and had little influence on H. pylori infection or gastric atrophydevelopment.