The
Centers for Disease Control and Prevention in the U.S. just announced an
investigation of a multistate outbreak of e-cigarette, or vaping, product use
associated lung injury (EVALI). By November there were over 1,800
confirmed and probable cases and 37 deaths.1 This opens the
safety of Electronic nicotine delivery systems (ENDS) to scrutiny
once more.
ENDS
promise to lower the risk of smoking-related disease, yet the WHO earlier this
year warned against their use.2 Before rushing to judgment, let’s
recap. Cancer Research UK and Public Health England both support vaping as less
harmful than smoking. Thousands of smokers have used ENDS to help them quit tobacco.3
Are they all wrong?
While the
pathology of vaping-associated lung injury is unknown, we do know the lungs are
meant only for air. Occupational and environmental exposure to inhaled toxic
compounds is known to cause lung damage. In some dramatic examples, lasting
respiratory impairment has resulted from a single-event exposure.4, 5
By contrast, smokers and vapers flood their lungs continually with substances
for which these delicate structures are not designed.
Findings
published in 2018 linked exposure to the ENDS vapour to cancer in mice.6
Regardless of the precise initiation of the inflammatory response, consumers
using ENDS might expect these devices not to be causing cancer at all. There is
also evidence that e-liquids can contain potentially toxic compounds in
addition to nicotine.7, 8
The WHO
suggest that ENDS carry warnings to flag their potential to cause
cardiorespiratory health problems, in part due to the diversity of products.
Today all major tobacco firms sell ENDS, but plentiful alternatives exist with
many consumers favouring e-liquids of uncertain origin and content. Of those
affected in the U.S. outbreak, almost 80% reported vaping nicotine with
tetrahydrocannabinol (THC) or cannabidiol (CBD) products and this
link must be examined. No similar outbreak has yet been reported, which may be
due to differences in regulation.9
Based on
pure risk assessment principles, inhaling possibly toxic substances to the
lungs must be contra-indicated. The lungs are intricate organs with a purpose
that bridges pure cardiopulmonary function with a systemic one. What we put
into our lungs, whether toxic or therapeutic, affects every aspect of our
bodies and health. Yet as an alternative to the known harm of inhaling tobacco
smoke ENDS likely represent a lesser of two evils. Since an estimated one in
every two cigarette smokers die as a direct result of their habit, any form of
harm reduction is to be welcomed.
Significant
short-term health risks are associated with spikes in air pollution, especially
toxic nitrogen oxides in diesel engine emissions. The urgent need to reduce
exposure to diesel particulates forced a dramatic U-turn in transport policies
worldwide.10 We haven’t yet seen research that shows similar
significant short-term health risks from e-cigarettes, but care is needed to
properly classify users of e-cigarettes.
The
widespread concurrent use of ENDS among cigarette smokers is of concern for
insurers seeking to differentiate smokers from non-smokers.11 Few
never-smokers bother with e-cigarettes, but dual use compromises any health
benefit and may not be associated with reduced exposure to tobacco-related
health risks.12 While ENDS may be causing less harm so far, they are
not harmless, and the emerging EVALI outbreak raises questions that cast
serious doubt over their long-term safety.
Endnotes
2. WHO
Report on the Global Tobacco Epidemic, 2019.
7. Lee M.S.,
et al., Nicotine, aerosol particles, carbonyls and volatile organic
compounds in tobacco- and menthol-flavored e-cigarettes. EnvironHealth 2017;
16: 42.
8. Lee M.S.,
et al., Endotoxin and (1→3)-β-Dglucan contamination in electronic
cigarette products sold in the United States. Environ Health Perspect 2019;
127: 47008.
No comments:
Post a Comment