Opium use and risk of bladder cancer: A multi-centre case-referent study in Iran

Maryam Hadji, Hamideh Rashidian, Maryam Marzban, Ahmad Naghibzadeh-Tahami, Mahin Gholipour, Elham Mohebbi, Roya Safari-Faramani, Monireh Sadat Seyyedsalehi, Bayan Hosseini, Mahdieh Bakhshi, Reza Alizadeh-Navaei, Lida Ahmadi, Abbas Rezaianzadeh, Abdolvahab Moradi, Alireza Ansari-Moghaddam, Azim Nejatizadeh, Soodabeh Shahidsales, Farshad Zohrabi, Reza Mohammadi, Mohammad Reza NowrooziHossein Poustchi, Dariush Nasrollahzadeh, Farid Najafi, Ali Akbar Haghdoost, Afarin Rahimi-Movaghar, Arash Etemadi, Mohammad Ali Mohagheghi, Reza Malekzadeh, Paul Brennan, Joachim Schüz, Paolo Boffetta, Elisabete Weiderpass, Farin Kamangar, Kazem Zendehdel, Eero Pukkala

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Background: Bladder cancer (BC) is the 10th most common type of cancer worldwide and the fourth most common type of cancer in Iran. Opium use is considered as one of the risk factors for BC. We aim to assess the association between various parameters of opium use, which in Iran is mainly ingested or smoked in various forms, and the risk of BC. Method: In this multi-centre case-referent study in Iran, 717 BC cases and 3477 referents were recruited to the study from May 2017 until July 2020. Detailed histories of opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure adjusted odds ratio (OR) and 95% confidence intervals (CI). The ORs were adjusted for age, gender, place of residence and pack-years of cigarette smoking. Results: Regular opium consumption was associated with an increased risk of BC (OR 3.5, 95% CI: 2.8, 4.3) compared with subjects who never used opium. Compared with continuous users, the risk decreased to one-Third for those who stopped opium more than 10 years ago. The adjusted OR for those who used both crude opium (teriak) and opium juice was 7.4 (95% CI: 4.1, 13.3). There was a joint effect of opium and tobacco (OR for users of both opium and tobacco 7.7, 95% CI: 6.0, 9.7). Conclusions: Regular opium use is associated with an approximately 4-fold risk for BC. The OR decreases along with the increasing time since stopping opium use.

Original languageEnglish
Pages (from-to)830-838
Number of pages9
JournalInternational Journal of Epidemiology
Issue number3
Publication statusPublished - 4 Mar 2022
Publication typeA1 Journal article-refereed


  • bladder cancer
  • opium

Publication forum classification

  • Publication forum level 3

ASJC Scopus subject areas

  • Epidemiology


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