ENDS, Cigarettes, and Respiratory Illness: Longitudinal Associations Among U.S. Youth.

ENDS use is highly prevalent among U.S. youth, and there is concern about its respiratory health effects. However, evidence from nationally representative longitudinal data is limited. Using youth (aged 12–17 years) data from Waves 1–5 (2013–2019) of the Population Assessment of Tobacco and Health Study, multilevel Poisson regression models were estimated to examine the association between ENDS use; cigarettes; and diagnosed bronchitis, pneumonia, or chronic cough. Current product use was lagged by 1 wave and categorized as (1) never/noncurrent use, (2) exclusive cigarette use, (3) exclusive ENDS use, and (4) dual ENDS/cigarette use. Multivariable models adjusted for age, sex, race and ethnicity; parental education; asthma; BMI; cannabis use; secondhand smoke exposure; and household use of combustible products. Data analysis was conducted in 2022–2023. A total of 7.4% of respondents were diagnosed with bronchitis, pneumonia, or chronic cough at follow-up. In the multivariable model, exclusive cigarette use (incident rate ratio=1.85, 95% CI=1.29, 2.65), exclusive ENDS use (incident rate ratio=1.49, 95% CI=1.06, 2.08), and dual use (incident rate ratio=2.70, 95% CI=1.61, 3.50) were associated with a higher risk of diagnosed bronchitis, pneumonia, or chronic cough than never/noncurrent use. These results suggest that ENDS and cigarettes, used exclusively or jointly, increased the risk of diagnosed bronchitis, pneumonia, or chronic cough among U.S. youth. However, dual use was associated with the highest risk. Targeted policies aimed at continuing to reduce cigarette smoking and ENDS use among youth, especially among those with dual use, are needed. [ABSTRACT FROM AUTHOR]