Dual Users of Cigarettes and E-Cigarettes at Highest Risk for Toxicants

Cigarette and Electronic Cigarette
Cigarette and Electronic Cigarette
Individuals who use both combustible and e-cigarettes have the highest risk for elevated concentration of toxicants.

Individuals who use both combustible and e-cigarettes have the highest risk for elevated concentration of toxicants, according to a study published in JAMA Network Open. Individuals who smoke exclusively combustible cigarettes have the next highest risk, followed by those who use only e-cigarettes.

This longitudinal, population-based cohort study included 247 participants who used only e-cigarettes, 2411 who smoked only combustible cigarettes, 792 dual users, and 1655 never users. The study period took place from  2013 to 2014, with cross-sectional analysis performed between 2016 and 2017. Researchers measured 50 biomarkers associated with tobacco exposure within 5 types of tobacco ingredients: volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), metals, tobacco-specific nitrosamines (TSNAs), and nicotine metabolites. Demographic features were compared using descriptive analyses such as 1-way variance analysis and Pearson χ2 tests. Tobacco user groups were compared through geometric mean biomarker concentrations.

Individuals who smoked only combustible cigarettes had biomarker concentrations 10% to 36% lower than those in dual users, in whom toxicant exposure was associated with cigarette use frequency. E-cigarette-only users had 10% to 98% lower biomarker concentrations (including nicotine, PAHs, TSNAs, and most VOCs) than combustible cigarette-only smokers, with similar concentrations for 3 VOCs and all metals. Concentrations of biomarkers (nicotine, certain metals, TSNAs, and VOCs) were 19% to 81% lower in never users compared with e-cigarette-only users.

Study limitations include a lack of differentiation between different generations of e-cigarettes at wave 1, a lack of sensitivity to the origins of certain biomarkers such as arsenic, which can come from diet or pollution;, and the potential for other toxicants not yet classified as harmful.

The researchers concluded that “current, exclusive e-cigarette use results in exposure to known toxicants. Toxicant exposure is greatest among dual users, and frequency of use of combustible cigarettes is positively correlated with tobacco product toxicant concentration. These findings provide evidence that using combusted tobacco cigarettes alone or in combination with e-cigarettes is associated with higher concentrations of potentially harmful tobacco constituents in comparison with using e-cigarettes alone. This study may provide a foundation for disease risk investigations in the PATH [Population Assessment of Tobacco and Health] Study population.”

Disclosures: ML Goniewicz, PharmD, PhD, reports financial associations with Johnson & Johnson and Pfizer.


Goniewicz ML, Smith DM, Edwards KC, et al. Comparison of nicotine and toxicant exposure in users of electronic cigarettes and combustible cigarettes [published online December 14, 2018]. JAMA Netw Open. doi:10.1001/jamanetworkopen.2018.5937