Association Between E-Cigarette Use and Cardiovascular Disease Among Never and Current Combustible-Cigarette Smokers

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 with 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 1.36; 95% confidence interval, 1.18-1.56); with consistent results in subgroup analyses of premature cardiovascular disease in women <65 years and men <55 years old. Conclusion Our results suggest significantly higher odds of cardiovascular disease among dual users of e-cigarettes + combustible cigarettes compared with smoking alone. These data, although preliminary, support the critical need to conduct longitudinal studies exploring cardiovascular disease risk associated with e-cigarette use, particularly among dual users.