A University of Michigan study found that while exclusive cigarette use was associated with an increased risk of self-reported incident diagnosed cardiovascular disease over a five-year period, use via electronic nicotine delivery systems (ENDS) was not linked to any statistically significant increase in the outcomes.
However, the study team said generally, the cardiovascular health effects of ENDS use are not well characterised, making it difficult definitively to assess ENDS as a potential harm reduction tool for adults who smoke regular cigarettes.
Study details
Longitudinal associations between exclusive and dual use of electronic nicotine delivery systems and cigarettes and self-reported incident diagnosed cardiovascular disease among adults
Jana Hirschtick, Steven Cook, Akash Patel, Geoffrey Barnes, Douglas Arenberg, Irina Bondarenko, David Levy, Jihyoun Jeon, Evelyn Jimenez Mendoza, Rafael Meza, Nancy Fleischer.
Published in Nicotine & Tobacco Research on 19 July 2022
Abstract
The cardiovascular health effects of electronic nicotine delivery systems (ENDS) use are not well characterised, making it difficult to assess ENDS as a potential harm reduction tool for adults who use cigarettes.
Methods
Using waves 1-5 of the Population Assessment of Tobacco & Health Study (2013-2019), we analysed the risk of self-reported incident diagnosed myocardial infarction (MI; 280 incident cases) and stroke (186 incident cases) associated with ENDS and/or cigarette use among adults aged 40+ using discrete time survival models. We employed a time-varying exposure lagged by one wave, defined as exclusive or dual established use of ENDS and/or cigarettes every day or some days, and controlled for demographics, clinical factors, and past smoking history.
Results
The analytic samples (MI=11,031; stroke=11,076) were predominantly female and non-Hispanic white with a mean age of 58 years. At baseline, 14.2% of respondents exclusively smoked cigarettes, 0.6% exclusively used ENDS, and 1.0% used both products. Incident MI and stroke were rare during follow-up (<1% at each wave). Compared to no cigarette or ENDS use, exclusive cigarette use increased the risk of MI (aHR 1.99, 95% CI 1.40-2.84) and stroke (aHR 2.26, 95% CI 1.51-3.39), while exclusive ENDS use (MI: aHR 0.61, 95% CI 0.12-3.04; stroke: aHR 1.74, 95% CI 0.55-5.49) and dual use (MI: aHR 1.84, 95% CI 0.64-5.30; stroke: aHR 1.12, 95% CI 0.33-3.79) were not significantly associated with the risk of either outcome.
Conclusions
Compared with non-use, exclusive cigarette use was associated with an increased risk of self-reported incident diagnosed cardiovascular disease over a five-year period, while ENDS use was not associated with a statistically significant increase in the outcomes.
Implications
Existing literature on the health effects of ENDS use has important limitations, including potential reverse causation and improper control for cigarette smoking. We accounted for these issues by using a prospective design and adjusting for current and former smoking status and cigarette pack years. In this context, we did not find that ENDS use was associated with a statistically significant increase in self-reported incident diagnosed myocardial infarction or stroke over a five-year period. While more studies are needed, this analysis provides an important foundation and key methodological considerations for future research on the health effects of ENDS use.
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