Scant evidence exists to support the association of opium use with head and neck cancer, limited to the larynx and oral cavity. In a multicenter case‐control study—Iran Opium and Cancer study, we recruited 633 cases of head and neck squamous cell carcinoma (HNSCC) (254 lip and oral cavity, 54 pharynx, 327 larynx and 28 other subsites within the head and neck) and 3065 frequency‐matched controls from April 2016 to April 2019. Odds ratios (ORs) for opium use and 95% confidence intervals (95% CIs) were obtained using mixed‐effects logistic regression because of heterogeneity among centers. The adjusted OR (95% CI) for regular opium use was 3.76 (2.96‐4.79) for all HNSCC combined. Strong dose‐response effects were observed by frequency or amount of use, and duration of use. Regular opium uses significantly increased the risk of HNSCC of the pharynx, larynx and other subsites within the head and neck with OR (95% CI) of 2.90 (1.40‐6.02), 6.55 (4.69‐9.13) and 5.95 (2.41‐14.71), respectively. The observed associations were significant even among never tobacco smokers (including cigarette and water‐pipe smoking). Moreover, by the multiplicative interaction scale, the effect of opium use could be varied by cigarette smoking on HNSCC, 8.16 (6.20‐10.74). For the first time, the current study showed opium users have an increased risk of several anatomic subsites of HNSCC.

Background: Several research priority-setting studies have been conducted in different countries, including the Islamic Republic of Iran. Aims: We conducted a systematic review and evaluated the quality of the priority-setting reports about health research in the Islamic Republic of Iran. Methods: English and Farsi databases were searched from January to July 2016 to extract reports (up to December 2015) about priority setting in health research in the Islamic Republic of Iran. We constructed a checklist to extract data from the identified studies. Articles were studied in detail and content analysis was carried out. Relevant items were scored and analysed using Microsoft Excel. Results: We identified 36 articles. Eight articles involved all the main stakeholders. About half the articles used valid criteria for ranking. Transparency was fulfilled in 13 articles. Upstream rules and regulations were ignored in 26 articles. An implementation plan was considered in 9 articles and context analysis was demonstrated in only 3. Conclusions: Developing standard packages for priority setting, training of researchers and improving the capacity of organizations may improve the quality of priority-setting studies in the future.