Etemadi A, et al. - Researchers compared carcinogen exposure across different, especially noncigarette, tobacco products, by analyzing 165 participants of the Golestan Cohort Study from northeastern Iran (60 never users of any tobacco, 35 exclusive cigarette, 40 exclusive (78% daily) waterpipe, and 30 exclusive smokeless tobacco [nass] users). Concentrations of 39 biomarkers of exposure in four chemical classes in baseline urine samples were measured (tobacco alkaloids, tobacco-specific nitrosamines [TSNA], polycyclic aromatic hydrocarbons [PAH], and volatile organic compounds [VOC]). Highest concentrations of tobacco alkaloids were seen among nass users. They noted elevated TSNA concentrations among all tobacco users, which correlated with nicotine dose. Compared to never tobacco users and nass users, both cigarette and waterpipe smokers displayed higher PAH and VOC biomarkers, which highly correlated with nicotine dose. The findings suggest a possible utility of most of these biomarkers for exposure assessment in a longitudinal study. In the Golestan Cohort, environmental exposure from nontobacco sources seemed to contribute to the presence of high levels of PAH metabolites.