Trends in urinary bladder cancer incidence in Sweden 1960-93 with special reference to histopathology, time period, birth cohort, and smoking
- Cite this article as:
- Thörn, M., Bergström, R., Johansson, AM. et al. Cancer Causes Control (1997) 8: 560. doi:10.1023/A:1018486111572
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This study investigates the incidence trends of urinary bladdercancer in Sweden from 1960 through 1993 (a total of 46,211 cases).Age-standardized incidence rates increased among men from 14.6 per 10 5 in1960 to 33.5 in 1993 and among women from4.8 to 8.8, corresponding to anaverage annual increase of 2.4 percent (95 percent confidence interval [CI])= 2.0-2.7 percent) and 1.1 percent (CI = 0.9-1.4 percent), respectively. Thelargest increase occurred in the oldest age-groups. The proportion ofpatients with transitional cell carcinoma increased in menfrom66.0 percent in1960-64 to 93.6 percent in 1990-93 and in women from 61.0 percent to 89.4percent. The proportion of patients with papillomas decreased, whereas thosewith adenocarcinoma and squamous cell carcinoma were stable. Regressionmodeling (based on the period 1960-89) showed a strong linear effect due toeither period and/or cohort. Among men, additional non-linear effects by bothperiod and cohort were obtained. T he cohort effects were more important.Cohort data on having smoked daily showed considerable similarities with theestimated cohort-effects. Our findings suggest that the increase of tobaccosmoking in successive generations can explain the increase in incidence ratesof bladder cancer in Sweden, whereas improved diagnostic activities andregistration are less likely to explain fully the changes in incidence rates.