E-Cigarette Use Trajectories and Respiratory Symptoms in Adolescents and Young Adults: Sustained Use Linked to Greater Symptom Frequency

OBJECTIVE: This study cross-sequentially examined three measures of self-reported respiratory symptoms and nicotine e-cigarettes (EC) use adjusting for past 30-day use of cannabis/tobacco, COVID-19, and lifetime asthma at baseline (T1) and 12-months (T2). METHOD: Data came from the Emerging Adulthood Health Project. AYAs aged 15-24 (N= 751) self-reported demographics, nicotine/cannabis use, and respiratory symptoms. EC use at T1-T2 was categorized into a) never use, b) non-escalating, c) increasing, or d) sustained use. Binary and linear logistic regressions examined outcomes at T2. RESULTS: At T1, participants (M age= 20.56 years [SD= 2.09 years]) were mostly female (n= 423 [56.6%]), White (n= 563 [75.3%]), and college students (n= 510 [68.0%]). In unadjusted analyses, EC sustained use had a significantly higher number of summed symptoms (binary; OR= 1.47, 95% CI [1.04, 2.07], p= .03) and more days with symptoms (OR= 1.64, 95% CI [1.16, 2.32], p= .006) compared to never EC use. In adjusted analyses, sustained EC use had higher American Thoracic Society Questionnaire scores (b=1.48, SE= 0.54, p=.0006) than never EC use, but the number of summed symptoms and days with symptoms became non-significant. Among participants experiencing any day with symptoms (N= 269), sustained (b= 2.05, SE=0.95, p=.03) and non-escalating use (b= 2.73, SE= 1.17, p= .02) was associated with more days with symptoms than never EC use in adjusted analyses. CONCLUSIONS: EC use behavior impacts self-reported frequency of respiratory symptoms among AYAs, with those who continue to use reporting more frequent symptoms, after adjusting for tobacco/cannabis use, COVID-19, and asthma.