Exposure to Environmental Tobacco Smoke: a Modifiable Factor of Hospitalization and Severity of Acute Bronchiolitis.

OBJECTIVE: The objective was to evaluate the associations of environmental tobacco smoke exposure with acute bronchiolitis and its severity among hospitalized children. METHODS: This case-control study with prospective follow-up was conducted at a tertiary care hospital (February 2017-December 2021). Infants hospitalized for bronchiolitis were enrolled as cases, and hospitalized children < 2 lt; 2 years of age without respiratory disease were recruited as controls. Serum cotinine was measured in all participants. Demographic and clinical data and household smoking habits were collected through parental interviews. Logistic regression was used to assess the association between environmental tobacco smoke exposure and bronchiolitis. Additionally, whether serum cotinine concentration was associated with admission to the pediatric intensive care unit and length of hospital stay in infants with bronchiolitis was investigated. RESULTS: In total, 251 infants (151 cases, 100 controls) were included; 52.6% of participants were exposed to environmental tobacco smoke, with a higher prevalence among the bronchiolitis group (59.6%vs. 42%; p = 0.006). Multivariate analysis revealed that environmental tobacco smoke exposure (OR: 1.93; 95% CI: 1.04-3.56) and prenatal maternal smoking (OR: 3.49; 95% CI: 1.22-9.95) were independently associated with hospitalization for bronchiolitis. Among the cases, serum cotinine levels > 5 ng/mL predicted prolonged length of hospital stay (OR: 4.99; 95% CI: 1.70-15.7), whereas prenatal smoking increased the risk for pediatric intensive care unit admission (OR: 4.73; 95% CI: 1.68-13.3). CONCLUSIONS: Pre- and postnatal environmental tobacco smoke exposure was associated with bronchiolitis and disease severity. Developing effective public health strategies to reduce such exposures among children is a priority.