Another study links e-cig use to cardiovascular disease, shows dual use riskier than just smoking

AD Osei and colleagues just published “The association between e-cigarette use and cardiovascular disease among never and current combustible cigarette smokers: BRFSS 2016 & 2017” in American Journal of Medicine.  While they did not find a statistically significant increase in risk of cardiovascular disease (coronary heart disease, myocardial infarction, or stroke) among e-cigarette only users, they did find a statistically significant increase in risk for dual users (i.e., people who added e-cigarettes to conventional cigarettes).  This finding is consistent with our findings, using the National Health Interview Survey and PATH, that dual use is more dangerous than just smoking.  This is an important finding because most adult e-cigarette users continue to smoke (i.e., are dual users). 

The fact that the authors did not find an effect of e-cigarettes alone may be because they stratified the sample on e-cig and cigarette use, which reduces the sample size for each comparison, and so the power to detect an effect.

In any event, their paper adds to the case that e-cigarettes have their own risk pattern; they are not just “cigarettes with less ‘bad stuff.’”

Here is the abstract.

BACKGROUND:  The prevalence of e-cigarette use in the United States has increased rapidly. However, the association between e-cigarette use and cardiovascular disease remains virtually unknown. Therefore, we aimed to examine the association between e-cigarette use and cardiovascular disease among never and current combustible cigarette smokers.

METHODS:  We pooled 2016 and 2017 data from the Behavioral Risk Factor Surveillance System (BRFSS), a large, nationally representative, cross-sectional telephone survey. We included 449,092 participants with complete self-reported information on all key variables. The main exposure, e-cigarette use, was further divided into daily or occasional use, and stratified by combustible cigarette use (never and current). Cardiovascular disease, the main outcome, was defined as a composite of self-reported coronary heart disease, myocardial infarction, or stroke.

RESULTS:  Of 449,092 participants, there were 15,863 (3.5%) current e-cigarette users, 12,908 (2.9%) dual users of e-cigarettes + combustible cigarettes, and 44,852 (10.0%) with cardiovascular disease. We found no significant association between e-cigarette use and cardiovascular disease among never combustible cigarette smokers. Compared to current combustible cigarette smokers who never used e-cigarettes, dual use of e-cigarettes + combustible cigarettes was associated with 36% higher odds of cardiovascular disease (Odds Ratio [OR], 1.36; 95% CI, 1.18-1.56); with consistent results in subgroup analyses of premature cardiovascular disease in women less than 65 years and men less than 55 years old.

CONCLUSION:  Our results suggest significantly higher odds of cardiovascular disease among dual users of e-cigarettes + combustible cigarettes compared to smoking alone. These data, though preliminary, support the critical need to conduct longitudinal studies exploring cardiovascular disease risk associated with e-cigarette use, particularly among dual users.

The full citation is  Osei AD, Mirbolouk M, Orimoloye OA, Dzaye O, Uddin SMI, Benjamin EJ, Hall ME, DeFilippis AP, Stokes A, Bhatnagar A, Nasir K, Blaha MJ.  The association between e-cigarette use and cardiovascular disease among never and current combustible cigarette smokers: BRFSS 2016 & 2017.  Am J Med. 2019 Mar 7. pii: S0002-9343(19)30211-6. doi: 10.1016/j.amjmed.2019.02.016. [Epub ahead of print].  It is available here.