Background: Unlike cigarettes, there is little information about the association between other tobacco products and the risk of gastroesophageal reflux disease (GERD) and esophageal adenocarcinoma.

Methods: We used the baseline data from the Pars Cohort Study conducted in southern Iran. In 2012, 9264 local residents between 40 and 75 years old were enrolled, with detailed information about lifestyle, including duration and frequency of tobacco use. GERD was defined based on questions assessing heartburn and regurgitation in the past 12 months, frequency and severity. Associations were calculated by logistic regression models adjusted for age, sex, education, cigarettes and body mass index.

Results: In the study, 25.4% of the participants had severe GERD (interfering with participants’ routines), 25.1% had frequent GERD (at least once a week) and 11.2% had both severe and frequent GERD, all more common among women (p < 0.001); 45.6% of women and 28.3% of men smoked waterpipes. Among people not using medications against reflux symptoms, there was an association between waterpipe smoking and severe [odds ratio (OR) = 1.18; 95% confidence interval (CI):1.04-1.35], frequent (OR = 1.16; 95% CI: 1.02-1.32) and severe and frequent reflux (OR = 1.30; 95% CI: 1.08-1.56). The associations increased with the duration of use, intensity and cumulative waterpipe-years, reaching an OR of 1.44 (95% CI: 1.12-1.86) for severe and frequent reflux in those who had smoked more than 48 waterpipe-years. There was effect modification by sex, and all the associations were only seen among women. Conclusion: The increasing trend in the association between cumulative waterpipe use and reflux disease among women is particularly important given the growing waterpipe tobacco epidemic in many populations.