Abstract
OBJECTIVES: We measured biomarkers of exposure among American Indian (AI) ENDS users, smokers, and dual users. METHODS: Urine was analyzed for total nicotine equivalents (TNE) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol(NNAL). Expired-air carbon monoxide (CO) was collected. Two analyses were performed. "CO analysis" included smokers and dual users whose CO was ≥ 6 ppm and ENDS users whose CO was < 6 ppm. "NNAL analysis" included smokers and dual users whose NNAL was ≥ 47.3 pg/mg, and ENDS users whose NNAL was < 47.3 pg/mg. Biomarkers were summarized by geometric means (GM) and compared with nonparametric tests. RESULTS: In both analyses, TNE was no different across the groups, and NNAL and CO were lower in ENDS users. In the NNAL analysis the GM of NNAL was 261.4, 6.1, and 228.0 pg/mg among smokers, ENDS users, and dual users (p < .001). Also in the NNAL analysis, the GM of CO was 14.7, 2.4, and 16.8 ppm among smokers, ENDS users, and dual users (p < .001). CONCLUSIONS: ENDS users did not differ in nicotine and had lower exposure to a lung carcinogen and a cardiovascular toxicant than smokers or dual users. Dual users and smokers did not differ in biomarker levels. Results should be used to inform tribal regulations and to educate the AI community on ENDS.