title: Can Opium Use Contribute to a Higher Risk of Colorectal Cancers? A Matched Case-control Study in Iran.
abstract: 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.
  
  
  CONCLUSIONS
  Opioid use can lead to an increased risk of CRCs. Therefore, it is necessary to implement preventive policies to control the use of opioids.
authors.affiliation: Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Naghibzadeh-Tahami
authors.affiliation: Health Services Management Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Vahid
authors.initials: V
authors.lastname: Yazdi Feyzabadi
authors.affiliation: Monash Center for Occupational and Environmental Health, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia; Research Center for Environmental Health Engineering, School of Public Health, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Khanjani
authors.affiliation: 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.
authors.forename: Ahad
authors.initials: A
authors.lastname: Ashrafi-Asgarabad
authors.affiliation: Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Hosniyeh
authors.initials: H
authors.lastname: Alizaeh
authors.affiliation: Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Vahid Reza
authors.initials: VR
authors.lastname: Borhaninejad
authors.affiliation: Medical Informatics Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Moradi-Joo
authors.affiliation: Gastroenterology and Hepatology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Zeinali
authors.affiliation: Endocrinology and Metabolism Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Zahedi
authors.affiliation: Research Center for Modeling in Health, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Aghaee-Afshar
authors.affiliation: Research Center for Modeling in Health, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Haghdoost
keywords: Case-control; Colorectal cancers; Iran; Opioid; Risk factor