ERICA: smoking is associated with more severe asthma in Brazilian adolescents

ObjectiveTo investigate the association between smoking and asthma, and possible associated factors in Brazilian adolescents.MethodsA cross-sectional, national, school-based study with adolescents aged 12–17 years, participants in the Study of Cardiovascular Risks in Adolescents (Estudo de Riscos Cardiovasculares em Adolescentes – ERICA). A total of 66,394 participants answered a self-administered questionnaire with questions about asthma, smoking, lifestyle and sociodemographic variables. Bivariate analysis between Current Asthma (CA) and Severe Asthma (SA) and the other study variables were performed using Chi-squared. Then, the crude and adjusted Prevalence Ratios (PR), and respective 95% Confidence Intervals (95% CI) of current asthma/severe asthma and smoking variables, corrected for sociodemographic and lifestyle variables, were estimated using generalized linear models with Poisson regression, logit link, and robust variance.ResultsThe prevalence of current asthma and severe asthma were significantly higher in adolescents who were exposed to: experimentation (current asthma: PR = 1.78, 95% CI: 1.51–2.09; severe asthma: PR = 2.01; 95% CI: 1.35–2.98); current smoking (current asthma: PR = 2.08, 95% CI: 1.65–2.64; severe asthma: PR = 2.29; 95% CI: 1.38–3.82); regular smoking (current asthma: PR = 2.25, 95% CI: 1.64–3.07; severe asthma: PR: 2.41; 95% CI: 1.23–4.73); and passive smoking (current asthma: PR = 1.47, 95% CI: 1.27–1.67; severe asthma: PR = 1.66; 95% CI: 1.19–2.32); these associations remained significant after adjustment.ConclusionsAsthma and smoking were significantly associated in Brazilian adolescents, regardless of the sociodemographic and lifestyle factors, notably in those with more severe disease.