The association between gender and pediatric respiratory morbidity

To evaluate the association between newborn gender and the risk for later pediatric respiratory morbidity.

A population based cohort analysis was performed by comparing the risk of long-term respiratory morbidity (until 18 years of age) according to gender. Respiratory morbidity included hospitalizations involving pneumonia, asthma, bronchitis, bronchiolitis, upper respiratory tract infection (URTI), influenza, and bronchiectasis. Deliveries occurred between the years 1991 and 2014 in a tertiary medical center. Kaplan-Meier survival curves were constructed to compare cumulative respiratory morbidity. A Cox proportional hazards model controlled for confounders.

During the study period 240 953 newborns met the inclusion criteria. Among them, 118 113 were females (49.0%) and 122 840 were males (51.0%). During the 18 years of follow-up, 13 719 (5.7%) different newborns were hospitalized with respiratory related morbidity. Males had significantly higher rates of respiratory morbidity as compared with females (6.4% vs 4.9% respectively, P < 0.001, OR 1.32, 95% CI 1.28-1.37). Specifically, pneumonia, bronchitis, asthma, bronchiolitis, and URTI were significantly more common in males. Males exhibited higher total cumulative respiratory morbidity (log rank P < 0.001), as well as higher cumulative morbidity in several sub-categories. These sub-categories included pneumonia, bronchitis, asthma, bronchiolitis, and URTI (P < 0.05 in all). The Cox regression model demonstrated male gender to be an independent risk factor for pediatric respiratory morbidity while adjusting for gestational age, birthweight, and other confounders (HR 1.29, 95% CI 1.25-1.34, P < 0.001).

Males are at an increased risk for pediatric respiratory morbidity, independent of obstetrical characteristics such as gestational age and birthweight.