Association of active and passive smoking with adolescent asthma: a systematic review and meta-analysis
Year: 2026
Type: review
Study designs: Systematic Review, Meta-Analysis
Abstract: To synthesize evidence on the association of active or passive smoking with asthma in adolescents. A comprehensive search of Embase, PubMed, Scopus, and Web of Science were conducted from inception to January 2026. Only human studies published in English were included. Observational studies evaluating active or passive smoking in adolescents aged 10–19 years were eligible. Studies reporting odds ratio (OR), hazard ratio (HR), relative risk (RR), prevalence ratio (PR), incidence rate ratio (IRR), or prevalence odds ratio (POR) with 95% confidence interval (95% CI) were included. Two reviewers independently screened studies. Key study characteristics, including authors, year, setting, age range, design, sample size, exposure type, asthma outcome, adjusted covariates, and effect estimates, were independently extracted and cross-verified by two reviewers, with discrepancies resolved by consensus. Seventy-seven studies met inclusion criteria, with 72 contributing to meta-analysis. Active smoking (adjusted odds ratio [aOR] = 1.16; 95% CI: 1.13–1.20), cigarette use (aOR = 1.19; 95% CI: 1.13–1.26), e-cigarette use (aOR = 1.13; 95% CI: 1.10–1.16), and passive smoking (aOR = 1.23; 95% CI: 1.17–1.29) were all significantly associated with asthma. Parental smoking conferred elevated risk (aOR = 1.85; 95% CI: 1.33–2.36), and exposure from friends showed the strongest association (aOR = 3.70; 95% CI: 1.63–5.78). Both active and passive smoking significantly increase asthma risk in adolescents, with both cigarette use and e‑cigarette use showing adverse associations. Friend smoking represents the most potent passive exposure. According to the GRADE assessment, the certainty of evidence for these associations was rated as very low, reflecting limitations in study design, confounder adjustment, and exposure measurement. Future studies should incorporate longitudinal designs, validated biomarkers, and standardized outcome measures to better characterize dose–response patterns and underlying mechanisms. What is already known on this topic. •Active and passive smoking are established contributors to respiratory morbidity in adolescents, yet prior reviews have largely focused on passive exposure and often reported inconsistent associations. •However, evidence has remained fragmented, with limited assessment of peer-related exposure, differential parental effects, or product-specific risks. What this study adds •This study provides the most comprehensive quantitative synthesis to date, demonstrating that both active and passive smoking significantly increase asthma risk in adolescents. •It identifies friend smoking as the strongest passive exposure source and reveals divergent effects of maternal versus paternal smoking. •Subgroup analyses further clarify risk gradients by exposure type, timing, study design, and asthma phenotype. How this study might affect research, practice or policy •These findings highlight the need for adolescent-focused tobacco control strategies that incorporate peer-network dynamics alongside family-level interventions. •The strong associations observed reinforce the urgency of stricter smoke-free policies, targeted school-based prevention programs, and surveillance systems that account for emerging tobacco products.
Source: BMC Public Health
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,290
OpenAlex ID: W7160699534