Nicotine and Toxicant Exposure among Individuals using both Combustible Cigarettes and E-cigarettes Based on Level of...

Dual use of combustible cigarettes and e-cigarettes is the most common multiple tobacco-use behavior in the United States, but its long-term health impact remains unclear. Biomarkers of exposure (BOE) can help identify potential health risks of dual use.

We analyzed data from 2,679 adult participants from Wave 5 of the Population Assessment on Tobacco and Health Study, a U.S. nationally representative study, including individuals reporting current exclusive cigarette use (n = 1,913), exclusive e-cigarette use (n = 316), and dual use (n = 450). Eight subgroups were created based on self-reported high/low (above/below mean) cigarettes per day (CPD) and days of e-cigarette use in past the 30 days (ECIG). Adjusted geometric mean concentrations were compared for total nicotine equivalents, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), three volatile organic compounds (VOCs), and heavy metals (lead and cadmium).

Individuals reporting dual use did not differ from those reporting exclusive cigarette use on CPD (13.1 vs. 11.8, respectively). Dual-use groups with high CPD had higher levels of NNAL and VOCs compared to those with low CPD (eg, NNAL for high CPD/high ECIG: 257.07 ng/mg creatinine vs. low CPD/high ECIG: 64.57 ng/mg creatinine, p < .001; high CPD/low ECIG: 312.02 ng/mg creatinine vs. low CPD/low ECIG: 144.11 ng/mg creatinine, p < .001). Cigarette use (dual or exclusive use) was generally associated with higher BOE than exclusive e-cigarette use, though metal exposure did not differ between groups.

Dual use and exclusive cigarette use are associated with higher toxicant exposure compared to exclusive e-cigarette use.

In this population-based cross-sectional study, individuals reporting dual use appear to have nicotine and toxicant exposure at least at the same level as those using cigarettes alone and higher than exclusive e-cigarette use (except for metals). Given the adverse health consequences of dual use, including potential cancer risk, our findings highlight the need for clinicians and public health practitioners to increase awareness of the potential risks associated with dual use.