The association of diabetes mellitus with subsequent internal cancers in the arsenic-exposed area of Taiwan

Diabetic patients had a 58% higher risk of any site internal cancer compared to non-DM individuals (HR, 1.58; 95% CI: 1.39-1.79) after adjusting for age, sex, education level, cigarette smoking, alcohol drinking, geographical location, cumulative arsenic exposure and history of hypertension or dyslipidemia. A significant association of DM with cancers of the stomach (HR, 1.75; 95% CI: 1.12-2.76), colon (HR, 1.76; 95% CI: 1.20-2.59), liver (HR, 2.46; 95% CI: 1.81-3.34), pancreas (HR, 2.80; 95% CI: 1.30-6.20) and lungs (HR, 1.35; 95% CI: 1.04-1.76) was observed. The association with lung, bladder and kidney cancer was largely confined to diabetic patients with arsenic level in consumed water ≧500 μg/L, while the association with other cancer sites did not show such an effect. With the adjustment of arsenic exposure, marked attenuation for the association was observed, suggesting high level arsenic exposure plays an important role in the development of diabetes mellitus and concomitantly lung, bladder and kidney cancer.