Opium as a risk factor for bladder cancer: a population-based case-control study in Iran

Background: Bladder cancer (BC) is the most common genitourinary system malignancy in humans. Consumption of opium and its derivatives, maybe a risk factor possibly in Iran. The aim of this study was to investigate the relationship between consumption of opium and its derivatives and the indident of BC. Methods: In an individauly matched case control study in Shiraz(located in south Iran),198 patients with BC and 196 healty individuals(matched in age, sex and residence(urbun/rural)) were investigated. Data about consumption of opium and its derivatives ,tobacco and alcohol and diet were collected using a structured valid and reliable questionnaire. Crude and adjusted odds ratios (ORs) were computed using conditional logistic regression models. Results: Opium consumption was associated with an increased risk of BC with an adjusted OR=3.9 (95 CI: 1.2-12.0). Moreover, a considerable dose-response relationship was observed between the opium consumption and its derivatives and the incidence of BC; comparing to no use, the odds ratios of low and high consumptions were 3.3 (95 CI: 0.5-23.1) and 4.9 (95 CI: 1.1-21.9) respectively. Conclusion: Opium consumption can be a potential strong risk factor for BC in Iran.