Opium use and mortality in Golestan Cohort Study: prospective cohort study of 50 000 adults in Iran
BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e2502 (Published 17 April 2012) Cite this as: BMJ 2012;344:e2502
- Hooman Khademi, research fellow12,
- Reza Malekzadeh, professor and director1,
- Akram Pourshams, associate professor1,
- Elham Jafari, research fellow1,
- Rasool Salahi, research fellow3,
- Shahryar Semnani, associate professor3,
- Behrooz Abaie, research fellow1,
- Farhad Islami, instructor14,
- Siavosh Nasseri-Moghaddam, associate professor1,
- Arash Etemadi, visiting fellow15,
- Graham Byrnes, biostatistics group head2,
- Christian C Abnet, investigator5,
- Sanford M Dawsey, senior investigator5,
- Nicholas E Day, professor6,
- Paul D Pharoah, senior clinical research fellow6,
- Paolo Boffetta, professor47,
- Paul Brennan, genetic epidemiology group head2,
- Farin Kamangar, professor and chairman158
- 1Digestive Disease Research Centre, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
- 2International Agency for Research on Cancer, Lyon, France
- 3Golestan Research Centre of Gastroenterology and Hepatology, Golestan University of Medical Sciences, Gorgan, Iran
- 4Institute for Translational Epidemiology and Tisch Cancer Institute, Mount Sinai School of Medicine, New York, NY, USA
- 5Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
- 6Departments of Oncology and Public Health and Primary Care, University of Cambridge, Cambridge, UK
- 7International Prevention Research Institute, Lyon
- 8Department of Public Health Analysis, School of Community Health and Policy, Morgan State University, Baltimore, MD, USA
- Correspondence to: R Malekzadeh malek@ams.ac.ir, P Brennan brennan{at}iarc.fr
- Accepted 20 February 2012
Abstract
Objectives To investigate the association between opium use and subsequent risk of death.
Design Prospective cohort study.
Setting The Golestan Cohort Study in north-eastern Iran collected detailed validated data on opium use and other exposures at baseline. Participants were enrolled between January 2004 and June 2008 and were followed to May 2011, with a follow-up success rate of over 99%.
Participants 50 045 participants aged 40-75 at baseline.
Main outcomes Mortality, all cause and major subcategories.
Results 17% (n=8487) of the participants reported opium use, with a mean duration of 12.7 years. During the follow-up period 2145 deaths were reported. The adjusted hazard ratio for all cause mortality associated with ever use of opium was 1.86 (95% confidence interval 1.68 to 2.06). Opium consumption was significantly associated with increased risks of deaths from several causes including circulatory diseases (hazard ratio 1.81) and cancer (1.61). The strongest associations were seen with deaths from asthma, tuberculosis, and chronic obstructive pulmonary disease (11.0, 6.22, and 5.44, respectively). After exclusion of people who self prescribed opium after the onset of major chronic illnesses, the associations remained strong with a dose-response relation.
Conclusion Opium users have an increased risk of death from multiple causes compared with non-users. Increased risks were also seen in people who used low amounts of opium for a long period and those who had no major illness before use.
Footnotes
We thank the study participants for their cooperation over many years; the behvarz (community health workers) in the study areas for their help; Goharshad Goglani, Karim Aghcheli, Mehdi Nouraei, Akbar Fazeltabar Malekshah, Nasser Rakhshani, Masoud Sotoudeh, Ali Yoonessi, Mohsen Sadatsafavi, Ramin Shakeri, Alireza Sadjadi, Amir Sharifi, Hossein Poustchi), and Mohammad R Akbari from DDRC; and Mattias Johansson from IARC. We also thank the general physicians, nurses, and nutritionists in the enrolment teams for their collaboration and assistance and Golestan University of Medical Sciences (Gorgan, Iran), the Golestan health deputies, and the chiefs of the Gonbad and Kalaleh health districts for their close collaboration and support.
Contributors: HK, RM, AP, FK, EJ, BA, CCA, SMD, PDP, PBo and PBr designed and implemented the study. HK, RM, AP, EJ, RS, SS, BA, FI, and S-NM acquired the data. HK, FK, and GB planned and conducted data analysis. HK, PBr, FK, GB, AE, NED, PDP, FI, PBo, and RM interpreted the data. HK, FK, and PBren drafted the manuscript. All authors reviewed the manuscript and approved the final version to be published. PBr and RM are guarantors.
Funding: The Golestan Cohort Study was supported by Tehran University of medical sciences (grant No: 81/15), Cancer Research UK (grant No: C20/A5860), the Intramural Research Program of the NCI, National Institutes of Health, and through various collaborative research agreements with the IARC. The study has also received special support from the Social Security Organization of Iran Golestan Branch.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the ethical review boards of Digestive Disease Research Centre (DDRC), International Agency for Research on Cancer (IARC), and National Cancer Institute (NCI). All participants gave written informed consent.
Data sharing: No additional data available
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