Hiatal hernia, reflux symptoms, body size, and risk of esophageal and gastric adenocarcinoma

BACKGROUND: Since the 1970s, incidence rates of esophageal and gastric cardia adenocarcinoma have risen substantially. Reasons for the increasing trends are not well understood. METHODS: A population-based, case-control study that included esophageal adenocarcinomas (n = 222), gastric cardia adenocarcinomas (n = 277), distal gastric adenocarcinomas (n = 443), and 1356 controls was conducted in Los Angeles County. Unconditional logistic regression was used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the 3 tumor types. RESULTS: After adjustment for demographic factors, smoking, and body size, both hiatal hernia and reflux symptoms emerged as significant independent risk factors. Risk of esophageal adenocarcinoma was increased 3-fold (adjusted OR, 3.61; 95% CI, 2.49-5.25) among those who had reflux symptoms but did not have hiatal hernia, 6-fold (adjusted OR, 5.85; 95% CI, 3.18-10.75) among those who had hiatal hernia but did not have reflux symptoms, and 8-fold (adjusted OR, 8.11; 95% CI, 4.75-13.87) among those who had both reflux symptoms and hiatal hernia. A similar risk pattern was found in relation to history of hiatal hernia and other reflux conditions. A more modest but still significant risk pattern was observed for gastric cardia adenocarcinoma. Among control subjects, there was a significant and positive association between increasing body mass index and history of hiatal hernia and/or reflux symptoms. CONCLUSIONS: Hiatal hernia, in combination with other reflux conditions and symptoms, was associated strongly with the risk of esophageal adenocarcinoma. These associations were more modest for gastric cardia adenocarcinomas. A significant and positive association between body size and history of hiatal hernia/reflux symptoms also was observed.