Opium as a Risk Factor for Bladder Cancer: A Population-based Case-control Study in Iran

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. 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. 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. Opium consumption can be a potential strong risk factor for BC in Iran.