Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 45 10 2016 12 14 1322 1331 Ahmad NAGHIBZADEH-TAHAMI Physiology Research Center, Institute of Neuropharmacology , Kerman University of Medical Sciences, Kerman, Iran Vahid YAZDI FEYZABADI Health Services Management Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran Narges KHANJANI Monash Center for Occupational and Environmental Health, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia AND Research Center for Environmental Health Engineering, School of Public Health, Kerman University of Medical Sciences, Kerman, Iran Ahad ASHRAFI-ASGARABAD Dept. of Epidemiology, Bam University of Medical Sciences, Kerman, Iran Social Determinants of Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran Hosniyeh ALIZAEH Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Vahid Reza BORHANINEJAD Medical Informatics Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran Mohammad MORADI-JOO Gastroenterology and Hepatology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran Masoud ZEINALI Endocrinology and Metabolism Research Center, Institute of Neuropharmacology , Kerman University of Medical Sciences, Kerman, Iran Mohammad Javad ZAHEDI Endocrinology and Metabolism Research Center, Institute of Neuropharmacology , Kerman University of Medical Sciences, Kerman, Iran Mahmoud AGHAEE-AFSHAR Research Center for Modeling in Health, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran Ali Akbar HAGHDOOST Research Center for Modeling in Health, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran 2016 10 23 2016 10 23 Background: Colorectal cancers (CRCs) including colon, rectum and anal cancers are the third most prevalent cancers in the world. There are strong evidence showing the risk of the cigarette smoking, alcohol use, low physical activity and some types of diets in CRCs; however, few studies explored the relationship between opium use and CRCs. This study aimed to investigate the association between opioid use and the incidence of CRCs. Methods: In a population-based matched case-control study in Kerman, Iran, 175 patients with colorectal cancers and 350 healthy controls (matched for age, sex, and place of residence) were interviewed from Sep 2014 to Nov 2014. Opium and its derivatives, cigarette, alcohol, and diet use were collected using a valid and reliable questionnaire. Conditional logistic regression was used to estimate odds ratios with 95% confidence intervals. Results: The use of opioids was associated with an increased risk of CRCs (adjusted odds ratio= 4. 5, 95% CI: 2. 4-8. 7). In addition, a dose-response relationship was observed between the cumulative use of opioids and the incidence of CRCs (with low use OR=3. 7; 95% CI: 1. 5-8. 6 and high use OR= 8. 0; 95% CI: 2. 9-21. 7). This dose-response relationship was also strong in patients with colon cancers, with OR= 3. 9 (95% CI: 1. 5-9. 9) and 9. 4 (95% CI: 3. 3-27. 0) for the low and high uses of opioids, respectively. Conclusion: Opioid use can lead to an increased risk of CRCs. Therefore, it is necessary to implement preventive policies to control the use of opioids.     https://ijph.tums.ac.ir/index.php/ijph/article/view/8071 https://ijph.tums.ac.ir/index.php/ijph/article/download/8071/5579