Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 18 9 2015 09 01 Opium as a Risk Factor for Bladder Cancer: A Population-based Case-control Study in Iran 0 0 EN Morteza Akbari Ahmad Naghibzadeh-Tahami Narges Khanjani Mohammad Reza Baneshi Elham Kamali Maryam Hesampour Bahman Nazemzadegan Ali-Akbar Haghdoost Journal Article 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 incidence of BC. METHODS: In an individually matched case-control study in Shiraz (located in the south of Iran), 198 patients with BC and 396 healthy individuals (matched in age, sex and residence (urban/rural)) were investigated. Data about consumption of opium and its derivatives, tobacco, 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 users, 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.