Vaping Dose, Device Type, and E-Liquid Flavor are Determinants of DNA Damage in Electronic Cigarette Users

Abstract

Introduction Despite the widespread use of electronic cigarettes, the long-term health consequences of vaping are largely unknown. Aims and Methods We investigated the DNA-damaging effects of vaping as compared to smoking in healthy adults, including “exclusive” vapers (never smokers), cigarette smokers only, and nonusers, matched for age, gender, and race (N = 72). Following biochemical verification of vaping or smoking status, we quantified DNA damage in oral epithelial cells of our study subjects, using a long-amplicon quantitative polymerase chain reaction assay. Results We detected significantly increased levels of DNA damage in both vapers and smokers as compared to nonusers (p = .005 and p = .020, respectively). While the mean levels of DNA damage did not differ significantly between vapers and smokers (p = .522), damage levels increased dose-dependently, from light users to heavy users, in both vapers and smokers as compared to nonusers. Among vapers, pod users followed by mod users, and those who used sweet-, mint or menthol-, and fruit-flavored e-liquids, respectively, showed the highest levels of DNA damage. The nicotine content of e-liquid was not a predictor of DNA damage in vapers. Conclusions This is the first demonstration of a dose-dependent formation of DNA damage in vapers who had never smoked cigarettes. Our data support a role for product characteristics, specifically device type and e-liquid flavor, in the induction of DNA damage in vapers. Given the popularity of pod and mod devices and the preferability of sweet-, mint or menthol-, and fruit-flavored e-liquids by both adult- and youth vapers, our findings can have significant implications for public health and tobacco products regulation. Implications We demonstrate a dose-dependent formation of DNA damage in oral cells from vapers who had never smoked tobacco cigarettes as well as exclusive cigarette smokers. Device type and e-liquid flavor determine the extent of DNA damage detected in vapers. Users of pod devices followed by mod users, and those who use sweet-, mint or menthol-, and fruit-flavored e-liquids, respectively, show the highest levels of DNA damage when compared to nonusers. Given the popularity of pod and mod devices and the preferability of these same flavors of e-liquid by both adult- and youth vapers, our findings can have significant implications for public health and tobacco products regulation.

The Toxicological Effects of e‐Cigarette Use in the Upper Airway: A Scoping Review

“…Additionally, flavoring compounds associated with common flavor names (eg, fruit) often vary across brands, which precludes accurate comparisons of their toxicological impact. Our review found 11 studies 14,17,18,22,28,32,34,39,52,60,64 that directly compared flavors against one another; however, only menthol and tobacco were included in more than 2 studies. Notably, tobacco flavoring appeared to be generally less harmful than the other flavors studied.…”

“…Tommasi et al 32 Oral epithelial cells from e-cigarette users displayed a dosedependent increase in DNA damage vs nonsmoking controls. There was no difference in DNA damage levels between e-cigarette users and smokers.…”

“…One study 22 compared the effects of 10 different flavored e-liquids versus unflavored e-liquid of the same brand on oral epithelial cells and showed that, in general, flavored e-liquids (±nicotine) were associated with increased oxidative stress, lipid peroxidation, cytotoxicity, and micronuclei formation compared to unflavored e-liquid. Eleven studies 14,17,18,22,28,32,34,39,52,60,64 directly compared various e-cigarette flavors to one another; however, the flavors varied between studies limiting the generalizability of results.…”

“…Twenty-six studies investigated the effects of flavored e-cigarettes. 12,14,[16][17][18]22,26,28,30,[32][33][34][37][38][39][40]47,50,52,56,58,59,61,63,64 The most commonly studied flavors were tobacco and mint/menthol, which appeared in 9/26 and 4/26 studies, respectively. One study 22 compared the effects of 10 different flavored e-liquids versus unflavored e-liquid of the same brand on oral epithelial cells and showed that, in general, flavored e-liquids (±nicotine) were associated with increased oxidative stress, lipid peroxidation, cytotoxicity, and micronuclei formation compared to unflavored e-liquid.…”

“…Twenty-five studies [13][14][15][16][19][20][21][22][23]26,27,32,35,37,40,41,45,46,49,51,55,58,61,63,64 directly compared the effects of exposure to e-cigarette vapor versus traditional cigarette smoke. In general, exposure to traditional cigarette smoke/condensate resulted in increased cytotoxicity, intracellular oxidative stress, DNA damage, and upregulated proinflammatory response compared with exposure to e-cigarette aerosol/condensate (±nicotine).…”