Bladder Cancer in Iran: Geographical Distribution and Risk Factors

Background: To study overall and province-specific trends of bladder cancer incidence in Iran during 2004-2008 and to evaluate the association between bladder cancer incidence and some factors. Methods: Data on 17792 bladder cancer patients and risk factors available at province level were used in Bayesian ecological setting. First, the overall and province-specific trends of risk were estimated. Then the effects of cigarette smoking, being overweight, fruits and vegetables consumption, and low levels of physical activity on trend were examined. The province-specific effects of significant factors were also assessed. The data were analyzed using R-INLA package. Results: The risk of developing bladder cancer was decreasing in Iran, 2004 - 2008 (RR = 0.95). Guilan and Semnan had the highest 5-year incidence (RR > 1.5). However, the risk increase compared to country Risk was the highest in East Azerbaijan and Tehran (DT > 0.1). Also direct and reverse association between smoking and fruit consumption and bladder cancer risk were established. Guilan, Semnan, Sistan and Baluchestan, and Ilam were the provinces affected the most by these factors. Conclusions: This study confirms previous findings and provides further evidence on protective effects of fruit consumption in bladder cancer. The results would be of value for governors to prioritize the province-specific demands on research, education, and improvements with respect to the identified risk factors.