Association between prenatal and neonatal risk factors and development of bronchiolitis in early life

Background: Bronchiolitis is the most common seasonal viral respiratory disorder in infants. However, risk factors for the development of bronchiolitis, particularly during pregnancy, remain unclear. Methods: A questionnaire was administered to the parents of the hospitalized infants with acute bronchiolitis to obtain information regarding patients' medical, family, and prenatal exposure history. Logistic regression with adjustment was performed to evaluate risk factors associated with bronchiolitis in the infants. Results: Among the enrolled patients, 55 (36.7%) were diagnosed as having bronchiolitis, and the majority (89%) of the patients had moderate-to-severe bronchiolitis. The bronchiolitis group had lower C-reactive protein levels than did the control group. Fewer patients in the bronchiolitis group developed fever. However, hospital stays were longer in the bronchiolitis group than in the control group. Respiratory syncytial virus was the most detected virus (23/26, 88.6%) in the bronchiolitis group. Male sex (odds ratio [OR], 5.71; 95% confidence interval [CI], 2.02-16.12; P < 0.001), antibiotic usage during pregnancy (OR, 27.2; 95% CI, 1.12-660.84; P = 0.04), and viral infection (OR, 49.3; 95% CI, 9.01-270.26; P < 0.001) during the postnatal period were significantly associated with hospitalization for acute bronchiolitis in the infants. By contrast, pet exposure during the perinatal period was significantly and negatively associated with acute bronchiolitis (OR = 0.21, 95% CI = 0.07-0.69, P < 0.01). Conclusion: Environmental exposures during pregnancy may affect respiratory health in offspring, and effective strategies should be developed to prevent bronchiolitis in early life.