Cancer Research U.K. published one of the only long-term studies to date comparing vaping to smoking cigarettes
Lion Shahab, PhD; Maciej L. Goniewicz, PhD; Benjamin C. Blount, PhD; Jamie Brown, PhD; Ann McNeill, PhD; K. Udeni Alwis, PhD; June Feng, PhD; Lanqing Wang, PhD; Robert West, PhD
Published: Ann Intern Med. 2017;166(6):390-400.
Source DOI: 10.7326/M16-1107
Background: Given the rapid increase in the popularity of e-cigarettes and the paucity of associated longitudinal health-related data, the need to assess the potential risks of long-term use is essential.
Objective: To compare exposure to nicotine, tobacco-related carcinogens, and toxins among smokers of combustible cigarettes only, former smokers with long-term e-cigarette use only, former smokers with long-term nicotine replacement therapy (NRT) use only, long-term dual users of both combustible cigarettes and e-cigarettes, and long-term users of both combustible cigarettes and NRT.
Design: Cross-sectional study.
Setting: United Kingdom.
Participants: The following 5 groups were purposively recruited: combustible cigarette–only users, former smokers with long-term (≥6 months) e-cigarette–only or NRT-only use, and long-term dual combustible cigarette–e-cigarette or combustible cigarette–NRT users (n = 36 to 37 per group; total n = 181).
Measurements: Sociodemographic and smoking characteristics were assessed. Participants provided urine and saliva samples and were analyzed for biomarkers of nicotine, tobacco-specific N-nitrosamines (TSNAs), and volatile organic compounds (VOCs).
Results: After confounders were controlled for, no clear between-group differences in salivary or urinary biomarkers of nicotine intake were found. The e-cigarette–only and NRT-only users had significantly lower metabolite levels for TSNAs (including the carcinogenic metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL]) and VOCs (including metabolites of the toxins acrolein; acrylamide; acrylonitrile; 1,3-butadiene; and ethylene oxide) than combustible cigarette–only, dual combustible cigarette–e-cigarette, or dual combustible cigarette–NRT users. The e-cigarette–only users had significantly lower NNAL levels than all other groups. Combustible cigarette–only, dual combustible cigarette–NRT, and dual combustible cigarette–e-cigarette users had largely similar levels of TSNA and VOC metabolites.
Limitation: Cross-sectional design with self-selected sample.
Conclusion: Former smokers with long-term e-cigarette–only or NRT-only use may obtain roughly similar levels of nicotine compared with smokers of combustible cigarettes only, but results varied. Long-term NRT-only and e-cigarette–only use, but not dual use of NRTs or e-cigarettes with combustible cigarettes, is associated with substantially reduced levels of measured carcinogens and toxins relative to smoking only combustible cigarettes.
Primary Funding Source: Cancer Research UK.