E-cigarette use and respiratory illnesses among US adults: An analysis of the Population Assessment of Tobacco and Health Study

Introduction: Electronic cigarettes (e-cigarette) entered the United States marketplace in 2007. Because of the chemical composition of e-cigarette liquid, there are concerns related to its effects on respiratory illnesses. Methods: Using Wave 4 (2016-2018) of the adult (>= 18 years of age) Population Assessment of Tobacco and Health study, logistic regression was used to quantify the association between e-cigarette use and any respiratory illness (asthma, chronic bronchitis, COPD, emphysema, or other lung or respiratory conditions). Age, gender, and the use of other tobacco products were assessed as modifiers of this relationship via interactions on the additive and multiplicative scales. Results: After adjustment, ever e-cigarette use was associated with a 1.32 (95 % confidence intervals [CI]:1.03, 1.69) greater odds of any respiratory illness compared with never e-cigarette users among U.S. adults. When comparing ever and never e-cigarette users, older adults (Odds Ratio [OR] = 1.65, 95 %CI:1.20, 2.26), and ever users of other tobacco products (OR = 1.77, 95 %CI:1.37, 2.29) had greater odds of reporting any respiratory illness than younger adults and those who never used other tobacco products. Among never e-cigarette users, men (OR = 1.51, 95 %CI:1.12, 2.04) were less likely to report any respiratory illness than women. Only the joint effect of age and e-cigarette use on any respiratory illness was statistically significant, suggesting this effect was greater than expected on the additive and multiplicative scales. Conclusion: These findings suggest that the relationship between e-cigarette use and any respiratory illness varies with age. Interventions and policies to reduce e-cigarette use should target high-risk groups for any respiratory illness.