Association Between the Persistence of Obesity and the Risk of Gastric Cancer: A Nationwide Population-Based Study.

Purpose There remains controversy about relationship between obesity and gastric cancer. We aimed to examine the association using obesity-persistence. Materials and Methods We analyzed a nationwide population-based cohort which underwent health check-up between 2009 and 2012. Among them those who had annual examinations during the last 5 years were selected. Gastric cancer risk was compared between those without obesity during the five years (never-obesity group) and those with obesity diagnosis during the five years (non-persistent obesity group; persistent obesity group). Results Among 2,757,017 individuals, 13,441 developed gastric cancer after median 6.78 years of follow-up. Gastric cancer risk was the highest in persistent obesity group (incidence rate (IR), 0.89/1,000 person-years; hazard ratio (HR), 1.197; 95% confidence interval (CI), 1.117-1.284), followed by non-persistent obesity group (IR, 0.83/1,000 person-years; HR, 1.113; 95% CI, 1.056-1.172) compared with never-obesity group. In subgroup analysis, this positive relationship was true among those <65 years old and male. Among heavy-drinkers, the impact of obesity-persistence on the gastric cancer risk far increased (non-persistent obesity: HR 1.297, 95% CI 1.094-1.538; persistent obesity: HR 1.351, 95% CI 1.076-1.698). Conclusion Obesity-persistence is associated with increased risk of gastric cancer in a dose-response manner, especially among male <65 years old. The risk raising effect was much stronger among heavy-drinkers.