Comparing the Effects of e-Cigarettes and Traditional Cigarettes on Asthma in Adolescents: A Systematic Review

Asthma is one of the most common chronic diseases among teenagers, and environmental factors such as smoking worsen the condition. The growing popularity of e-cigarettes raises concerns over their potential effects on asthma in adolescents compared to traditional cigarettes. This systematic review sought to evaluate the differences between e-cigarettes and traditional cigarettes in relation to asthma diagnosis, exacerbations, and symptoms in adolescents using quantitative studies conducted between 2015 and July 2025. Following PRISMA guidelines, we searched PubMed, Scopus, and the Web of Science and found 427 articles. After removing duplicates (n=188) and ineligible studies (n=229), we included 10 studies (1 cohort, 9 cross-sectional). Inclusion criteria included focus on adolescents, comparison of e-cigarettes and traditional cigarettes, and studies with asthma-related outcomes. Study quality was evaluated using Newcastle-Ottawa Scale (NOS; scores 6-8/10). Extracted data were narratively synthesized and comparatively analyzed across exposure groups due to heterogeneity in study design, outcomes, and effect measures. e-cigarettes were found to increase the likelihood of developing asthma more than traditional cigarettes among adolescents (AOR=1.10-1.30). Statistically significant relationships were also detected between exacerbations of asthma and e-cigarette use (AOR=2.13; APR=1.54-1.85). The impact of traditional cigarettes (AOR=0.80-8.49) was mixed. The highest risk was observed in dual users. The sexual minority and non-Hispanic Black youth showed greater susceptibility. Self-reporting, along with data obtained from cross-sectional designs, created a lack of causation. Both e-cigarettes and traditional cigarettes were associated with increased asthma-related outcomes, with the highest risk observed in dual users. There is a need for aggressive policies including flavor and age restrictions, as well as focused policies for those most at risk. To understand the strategies needed to lessen the burden of asthma in children and youth, clinical designed longitudinal studies will help identify the specific devices and causational factors.