Diabetes and risk of subsequent gastric cancer: a population-based cohort study in Taiwan

Epidemiological data concerning the association between diabetes and the subsequent development of gastric cancer are controversial. This population-based retrospective cohort study investigated the subsequent risk of gastric cancer for diabetic patients.From claims data of the universal health insurance of Taiwan, we identified 19,625 persons aged ≥20 years newly diagnosed with diabetes during 2000-2005. A comparison group (n = 78,500), frequency matched by age, sex, and calendar year, was randomly selected from people without diabetes. Incidence and hazard ratios (HR) of gastric cancer were ascertained during the follow-up period until 2008. We also explored associations of antidiabetic medicines with the incidence of gastric cancer.During the follow-up period, 47 subjects in the diabetic group and 216 subjects in the comparison group suffered gastric cancer, with the incidence rates of 4.34 and 4.86 per 10,000 person-years, respectively. During the first 4 years after diabetes diagnosis, the incidence of gastric cancer was relatively low in diabetic patients [adjusted HR = 0.63; 95% confidence interval (CI) = 0.42-0.97]. However, after that time, the diabetic group had a 76% (95% CI = 1.06-2.91) higher risk of developing gastric cancer than the comparison group. In diabetic patients, alpha-glucosidase inhibitors were associated with a significantly decreased risk of gastric cancer (adjusted HR = 0.38; 95% CI = 0.15-0.96).Our findings suggested that the association between diabetes and subsequent risk of gastric cancer may vary over time. Increased risk of gastric cancer was observed in patients with longer duration of diabetes.