Age-related risk of mortality from bladder cancer in diabetic patients: A 12-year follow-up of a national cohort in Taiwan

Background. To compare bladder cancer mortality between diabetic patients and the general population. Materials and methods. Yearly sex-specific mortality rates for age 25-64, 65-74, and 75 years in Taiwanese general population for 1995-2006 were calculated; 113,347 diabetic men and 131,573 diabetic women aged 25 years recruited in 1995-1998 were followed prospectively. Results. In the general population, 4,943 men and 2,291 women died of bladder cancer, and aging was associated with increased risk. Although the trend of crude mortality was increasing in either sex, the trend of age-standardized rates had been steady. The average crude and age-standardized mortality rates were 5.35 and 5.98 (per 100,000 population), respectively, for men; and were 2.63 and 3.02 for women. A total of 224 diabetic men and 126 diabetic women died of bladder cancer with crude mortality of 26.0 and 11.9 per 100,000 person-years, respectively. The relative risk of bladder cancer mortality (95% confidence interval) for diabetic patients was 2.18 (1.75-2.72), 2.50 (2.06-3.04), and 5.95 (4.57-7.74), in men, and 1.34 (0.96-1.89), 2.48 (1.92-3.19), and 7.44 (5.46-10.15), in women, for ages 75, 65-74, and 25-64 years, respectively. Conclusions. Diabetic patients had a higher risk of bladder cancer mortality, which is more remarkable in the younger population.