Cigarette Smokers Versus Cannabis Smokers Versus Co-users of Cigarettes and Cannabis: A Pilot Study Examining Exposure to Toxicants

Abstract Introduction Studies suggest tobacco and cannabis co-users may experience greater toxicant exposure than exclusive cigarette (ET) smokers. No study has systematically tested differences in toxicant exposure among co-users, exclusive cannabis (ECa) smokers, and ET smokers. Aims and Methods Adult daily cigarette smokers and/or weekly cannabis smokers completed two laboratory visits. Co-users (n = 19) tested positive for urinary 11-nor-9-carboxy-Δ 9-tetrahydrocannabinol (THCCOOH), self-reported cannabis use ≥1 per week, and smoked ≥5 cigarettes per day (CPD). ET smokers (n = 18) denied past month cannabis use, tested negative for urinary THCCOOH and smoked ≥5 CPD. ECa smokers (n = 16) tested positive for urinary THCCOOH, self-reported cannabis use ≥1 per week, and denied past month tobacco use (NicAlert .05). Conclusions Co-users and ET smokers demonstrated comparable levels of biomarkers of exposure to harmful constituents despite smoking similar amounts of tobacco. ECa smokers demonstrated lower levels of toxicant exposure for most biomarkers. Implications Although ECa smokers are exposed to significantly lower levels of harmful constituents compared with co-users and exclusive cigarette smokers, this group is still exposed to higher levels of toxicants than observed in studies of nonsmokers. Additionally, these three groups were exposed to similar levels of phenanthrene tetraol. It is important to account for cannabis use in studies examining biomarkers of exposure among cigarette smokers. Additionally, further research is needed examining exposure to harmful chemicals among various types of cannabis and tobacco users.