Clinical risk factors at 3 months of age for the development of bronchial asthma at 36 months of age

Background: We examined the associations between factors evident at the routine 3-month well-child visit (WCV) and the risk of developing 36-month parent-reported physician-diagnosed bronchial asthma (BA). Methods: This longitudinal study was conducted in Nagoya City, Japan, and included 40,242 children who qualified for the 3-month WCVs in the city between April 1, 2016 and March 31, 2018. In total, 22,052 (54.8%) questionnaires linked to their 36-month WCVs were analyzed. Results: The prevalence of BA was 4.5%. The multivariable Poisson regression model identified male sex (adjusted risk ratio [aRR], 1.59; 95% confidence interval [CI]: 1.40–1.81), born in autumn (aRR, 1.30; 95% CI: 1.09–1.55), having at least one sibling (aRR, 1.31; 95% CI: 1.15–1.49), wheeze history before 3-month WCVs, with clinic/hospital visit: aRR, 1.99; 95% CI: 1.53–2.56; hospitalization: aRR, 2.99; 95% CI: 2.09–4.12, eczema with itch (aRR, 1.51; 95% CI: 1.27–1.80), paternal history of BA (aRR, 1.98; 95% CI: 1.66–2.34), maternal history of BA (aRR, 2.11; 95% CI: 1.77–2.49), and rearing pets with fur (aRR, 1.35; 95% CI: 1.15–1.58) were independent risk factors for BA at 36 months of age. The combination of severe wheeze history (with clinic/hospital visit or hospitalization) and maternal and paternal BA could identify high-risk infants whose prevalence of BA was 20%. Conclusions: The combined assessment of important clinical factors enabled us to identify high-risk infants set to derive optimal benefit from health guidance provided to the parent or caregiver of the child or infant at WCVs.