Case-control study of urinary bladder cancer in metropolitan Nagoya

We conducted a population-based case-control study of patients with bladder cancer and of controls drawn randomly from the general population of Metropolitan Nagoya and interviewed both groups. The incidence rates of bladder cancer were 2.42 and 7.05/100,000 for females and males, respectively. The analysis, based on 293 patients and 589 controls who were frequency matched for age, sex, and residence, provided the following major findings. Age-adjusted relative risks of 1.89 (1.15-3.10) and 3.53 (1.71-7.27) were found in male and female cigarette smokers, respectively. Significant relative risk was also found in males who drank cocoa. Elevated risk with a dose-response relationship was observed among women who used hair dye and who smoke, but this risk was insignificant, with the disappearance of a dose-response relationship, when it was adjusted for smoking. Age- and smoking-adjusted relative risk of coffee drinking was insignificant with no dose-response relationship. Relative risk of artificial sweetener use was below 1 with adjustment for age and smoking. Intake of alcoholic beverages and cola was insignificantly associated. Reduced risk of significance was suggested for the intake of black tea and matcha (powdered green tea) in females and of fruit juice in males.