Is opium use related to the increased risk of oral cavity cancers? A case-control study in Iran

Oral cavity cancers (OCCs) are the sixth most prevalent cancers in the world. There are strong evidences showing the risk of the cigarette smoking, alcohol use, poor oral hygiene and some types of diets in OCCs; however, few studies explored the relationship between opium and its derivatives (O&D) use and OCCs incidence. The aim of this study was to investigate the relationship between consumption of O&D and the incidence of OCCs. In a case-control; 133 patients with OCCs and 266 healthy controls matched by age, sex, and place of residence were included. Data, including cigarette smoking, O&D, alcohol and others tobacco (Nass, pipe and hookah) use and diet, were collected using a structured questionnaire. The relation between the use of O&D and OCCs was evaluated using conditional logistic regression. Opium ever-use was associated with an increased risk of OCCs (Adjusted Odds Ratio (AOR) =2.36, 95 % CI: 1.16–4.78). A dose-response relation was observed between the amount of daily O&D use and OCCs; and the relation was stronger in high users (AOR for low users = 1.38, 95 %CI: 0.58–3.24 and AOR for high users = 4.85, 95 % CI:1.79–13.11). Those who used opium for more than 18 years were highly at risk of OCCs (AOR= 5.04, 95 % CI, 2.00–12.68). Also, OCCs was higher among subjects starting the use of O&D at younger ages (≤ 50 years old vs never users AOR = 3.32, 95 % CI: 1.19–9.23). The smoking method of consuming O&D increased the odds of getting OCCs more than twice (AOR= 2.02, 95 % CI, 1.03–3.94), and using both smoking and oral consumption simultaneously, increased the odds of getting OCCs more than 8 times (AOR= 8.57, 95 % CI, 1.68–43.70). Also, the use of other tobacco products (Nass, pipe and hookah) increases the odds of getting OCCs by 4 times (AOR= 3.90, 95 % CI, 1.12–13.57) The results showed that opium use is probably a dose related risk factor for oral cavity cancers. Therefore, it is necessary to implement preventive policies to control the use of opioids. [Display omitted] •The results of the present study showed that opium consumption strongly increases the risk OCCs.•There was a dose-response relationship between O&D use and the occurrence of OCCs.•The theory of opium being carcinogenic was confirmed.•Considering the increasing medical and non-medical use of opioids, the future consequences of these substances on oral cavity cancers should be considered.