Exposure to Tobacco Specific Nitrosamines among people who vape,
smoke or do neither. A Systematic Review and Meta Analysis Abstract
Background: 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.
Methods: Databases were searched between August
2017-March 2022, using vaping related terms. Peer-reviewed
articles reporting TSNA metabolites (NNAL,NNN,NAB,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 randomised 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.
Time:2023 Nov 11