Objective: Several studies have shown associations between diabetes and various types of cancer other than gastric cancer. The aim of this cohort study was to evaluate the impact of fasting plasma glucose (FPG) levels on gastric cancer occurrence.
Research design and methods: A total of 2,466 Japanese subjects aged > or =40 years were stratified into three groups according to FPG tertiles (<5.3 mmol/l, low FPG; 5.3-5.8 mmol/l, modest FPG; >5.8 mmol/l, high FPG) and followed up prospectively for 9 years.
Results: During the follow-up, 66 subjects experienced gastric cancer. In men, the age-adjusted incidences were significantly higher in the modest-FPG (7.0 per 1,000 person-years, P < 0.05) and high-FPG (7.2, P < 0.05) groups than in the low-FPG group (2.2). In women, the high-FPG group also had a significantly higher age-adjusted incidence of gastric cancer compared with the low-FPG group (2.5 vs. 0.8, P < 0.05). The multivariate analysis with Cox's proportional hazards model revealed that the risks of gastric cancer in the modest-FPG (relative risk [RR] 2.3 [95% CI 1.1-5.0]) and high-FPG (3.1 [1.5-6.4]) groups were significantly higher than that in the low-FPG group, even after adjusting for other comprehensive risk factors, including Helicobacter pylori status, smoking, and dietary factors. However, this FPG-cancer association was observed only among H. pylori-seropositive subjects.
Conclusions: Our findings suggest that a modest increase in FPG is a risk factor for gastric cancer and that hyperglycemia is a possible cofactor increasing the risk posed by Helicobacter pylori infection.