Association of hookah and nass use with GERD symptoms in never cigarette smokers.

Controls are those with no heartburn or regurgitation. Numbers may not add up to the total numbers due to missing data. The odds ratios (95% confidence intervals) were adjusted for age, sex, ethnicity, place of residence, education, wealth score, body mass index, physical activity, and consumption of alcohol, opium, and the other tobacco product shown in this table (hookah or nass).