The association between e-cigarette use and asthma among never combustible cigarette smokers: behavioral risk factor surveillance system (BRFSS) 2016 & 2017

BACKGROUND: E-cigarette use prevalence has grown rapidly in the US. Despite the popularity of these products, few acute exposure toxicity studies exist, and studies on long-term pulmonary health effects are limited. E-cigarette users who are never combustible cigarette smokers (sole users) constitute a unique group of young adults that may be at increased risk of bronchial hyperreactivity and development of asthma. Given the public health concern about the potential pulmonary health effects of sole e-cigarette use, we aimed to examine the association between e-cigarette use and asthma among never combustible cigarette smokers. METHODS: We pooled 2016 and 2017 data of the Behavioral Risk Factor Surveillance System (BRFSS), a large, cross-sectional telephone survey of adults aged 18 years and older in the U.S. We included 402,822 participants without any history of combustible cigarette smoking (defined as lifetime smoking < 100 cigarettes) and with complete self-reported information on key variables. Current e-cigarette use, further classified as daily or occasional use, was the primary exposure. The main outcome, asthma, was defined as self-reported history of asthma. We assess the relationship of sole e-cigarette use with asthma using multivariable logistic regression adjusting for age, sex, race, income, level of education and body mass index. RESULTS: Of 402,822 never combustible cigarette smokers, there were 3103 (0.8%) current e-cigarette users and 34,074 (8.5%) with asthma. The median age group of current e-cigarette users was 18–24 years. Current e-cigarette use was associated with 39% higher odds of self-reported asthma compared to never e-cigarette users (Odds Ratio [OR], 1.39; 95% confidence interval: 1.15, 1.68). There was a graded increased odds of having asthma with increase of e-cigarette use intensity. The odds ratio of self-reported asthma increased from 1.31 (95% confidence interval: 1.05, 1.62) in occasional users to 1.73 (95% confidence interval: 1.21, 2.48) in daily e-cigarette users, compared to never e-cigarette users. CONCLUSION: Our findings from a large, nationally representative survey suggest increased odds of asthma among never combustible smoking e-cigarette users. This may have potential public health implications, providing a strong rationale to support future longitudinal studies of pulmonary health in young e-cigarette-using adults.