Affiliation:
1. Addictions Department, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College , London , UK
2. NIHR HPRU Environmental Exposures and Health , London , UK
3. SPECTRUM Consortium , London , UK
4. NIHR ARC South London, Oxford , UK
5. Radiation, Chemical and Environmental Hazards, UK Health Security Agency (UKHSA)
Abstract
Abstract
Introduction
Smoking exposes people to high levels of Tobacco-Specific Nitrosamines (TSNAs), which include potent carcinogens. We systematically reviewed TSNA exposure between people smoking, vaping, and doing neither.
Aims and Methods
Databases were searched between August 2017–March 2022, using vaping-related terms. Peer-reviewed articles reporting TSNA metabolites (NNAL, NNN, NAB, and NAT) levels in bio-samples among adults exclusively vaping, exclusively smoking, or doing neither were included. Where possible, meta-analyses were conducted.
Results
Of 12 781 identified studies, 22 were included. TSNA levels fell substantially when people who smoke switched to vaping in longitudinal studies and were lower among people who vaped compared to smoked in cross-sectional studies. Levels of TSNAs were similar when comparing people who switched from smoking to vaping, to those who switched to no use of nicotine products, in longitudinal studies. Levels were higher among people who vaped compared to people who neither vaped nor smoked in cross-sectional studies.
When comparing people who vaped to smoked: pooled urinary NNAL was 79% lower across three randomized controlled trials and 96% lower across three cross-sectional studies; pooled NAB was 87% lower and NAT 94% lower in two cross-sectional studies. When comparing people who neither vaped nor smoked to people who vaped, pooled urinary NNAL was 80%, NAB 26%, and NAT 27% lower in two cross-sectional studies. Other longitudinal data, and NNN levels could not be pooled.
Conclusions
Exposure to all TSNAs was lower among people who vaped compared to people who smoked. Levels were higher among people who vaped compared to people who neither vaped nor smoked.
Implications
As well as TSNAs, there are many other toxicant exposures from smoking and vaping that can increase the risk of disease. However, it is likely that the reduced exposure to TSNAs from vaping relative to smoking reduces the risk to health of those who use vaping products to quit smoking. Future high-quality research, with robust definitions of exclusive vaping and smoking, and accounting for TSNAs half-lives, is needed to fully assess exposure to TSNAs among people who vape.
Funder
National Institute for Health Research Health Protection Research Unit
Health Security Agency
Imperial College London
UK Society
Publisher
Oxford University Press (OUP)
Subject
Public Health, Environmental and Occupational Health
Cited by
1 articles.
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1. Electronic cigarettes for smoking cessation;Cochrane Database of Systematic Reviews;2024-01-08