Comparative effects of cigarette smoking, e-cigarette use, and dual use on pulmonary function, exercise capacity, and quality of life in young adults: a cross-sectional study

Background Tobacco smoking constitutes a primary cause of preventable cardiovascular and pulmonary diseases on a global scale. While smoking rates fall, e-cigarette use rises, especially in youth. Objective Assess effects of smoking, vaping, and dual use on lung function, exercise capacity and quality of life. Methods Participants were classified into five groups: Control, Cigarette use only, E-cigarettes use only, Ex-cigarette smoker current vaper, and Dual users (use of both e-cigarettes and combustible cigarettes). Participants performed spirometry, six minute walk test (6MWT) and completed health related quality of life (HRQoL) questionnaire. Results A total of 222 participants, 86.9% were male, with median age 26 years. Age and body mass index (BMI) showed no significant differences across groups. Cigarette-only and dual users reported 20 cigarettes/day with 5–7 years smoking duration, while e-cigarette use duration was 4–5 years among exclusive vapers, ex-smoker vapers, and dual users. Spirometry revealed impairments: Forced expiratory volume in the first second (FEV 1 ; % predicted) was lower across groups versus controls ( H = 80.69, df = 4, p < 0.001, η 2 = 0.35), lowest in dual users. Forced vital capacity (FVC; L) showed no differences, while FVC (% predicted) decreased in smokers and dual users. FEV 1 /FVC ratio was reduced ( H = 66.54, df = 4, p < 0.001, η 2 = 0.29), most in dual users. 6MWT showed no group differences. HRQoL indicated decline in physical functioning ( H = 35.11, p < 0.001, η 2 = 0.14), role limitations due to physical health social functioning, and emotional wellbeing, lowest in cigarette-only and dual users. Conclusion Young adults using cigarettes and e-cigarettes showed impaired lung function and quality of life compared to never-users. Daily dual users showed the greatest declines, while former smokers using e-cigarettes showed intermediate outcomes. Exclusive e-cigarette users exhibited least impairment.