Relationships between lung function, allergy, and wheezing in urban children

Background Allergic sensitization and low lung function in early childhood are risk factors for subsequent wheezing and asthma. However, it is unclear how allergic sensitization impacts lung function over time. Objective To test whether allergy influences lung function and whether these factors synergistically increase the risk of continued wheezing in childhood. Methods We analyzed longitudinal measurements of lung function (spirometry, impulse oscillometry) and allergic sensitization (aeroallergen skin tests, serum allergen-specific IgE) throughout early childhood in the Urban Environmental and Childhood Asthma study which included high-risk urban children living in disadvantaged neighborhoods. Intraclass correlation coefficients (ICC) were calculated to assess lung function stability. Cluster analysis identified low, medium, and high allergy trajectories, which were compared to lung function and wheezing episodes in linear regression models. A variable selection model assessed predictors at age 5 for continued wheezing through age 12. Results Lung function adjusted for growth was stable (ICC 0.5–0.7) from ages 5–12 years and unrelated to allergy trajectory. Lung function and allergic sensitization were associated with wheezing episodes in an additive fashion. In children with asthma, measuring lung function at age 5 added little to the medical history for predicting future wheezing episodes through age 12. Conclusion In high-risk urban children, age-related trajectories of allergic sensitization were not associated with lung function development, however, both indicators were related to continued wheezing. These results underscore the importance of understanding early life factors that negatively impact lung development and suggest that treating allergic sensitization may not alter lung function development in early to mid-childhood.