Prospective study of e-cigarette use and respiratory symptoms in adolescents and young adults

RationaleElectronic cigarette (e-cigarette) aerosol contains volatile aldehydes, including flavourings and oxidant metals with known pulmonary toxicity. ObjectivesTo evaluate the associations of e-cigarette use with symptoms of wheeze, bronchitic symptoms and shortness of breath (SOB) across 4 years of prospective data. MethodsParticipants completed questionnaires on respiratory symptoms and past 30-day e-cigarette, cigarette and cannabis use in 2014 (wave 1; N=2094; mean age 17.3 years, SD=0.6 years). Follow-up information was collected in 2015 (wave 2; n=1609), 2017 (wave 3; n=1502) and 2018 (wave 4; n=1637) using online surveys. Mixed-effects logistic regression models evaluated associations of e-cigarette use with respiratory symptoms. Measurements and main resultsParticipants were mostly Hispanic white (51.8%) and evenly representative by sex (49.6% female; 50.4% male). Compared with never e-cigarette users, past 30-day e-cigarette users reported increased odds of wheeze (OR 1.95; 95% CI 1.39, 2.72), bronchitic symptoms (OR 2.10; 95% CI 1.61, 2.73) and SOB (OR 1.81; 95% CI 1.25, 2.60), adjusting for study wave, age, sex, race, lifetime asthma diagnosis and parental education. Effect estimates were attenuated (wheeze (OR 1.48; 95% CI 1.05, 2.09), bronchitic symptoms (OR 1.58; 95% CI 1.20, 2.07), SOB (OR 1.52; 95% CI 1.04, 2.22)), after adjusting additionally for current cigarette use, cannabis use and secondhand exposure to e-cigarettes/cigarettes/cannabis. ConclusionsE-cigarette use in young adults was associated with respiratory symptoms, independent of combustible cannabis and cigarette exposures.