EARLY exposure to household dog allergens was associated with a reduced risk of asthma and improved lung function in childhood, according to findings from a large population-based cohort.
Asthma in children is known to result from complex gene and environment interactions, yet the specific role of allergen exposure in infancy remains unclear. Investigators conducted an analysis within the CHILD study, focusing on indoor allergen exposure during the first months of life and its relationship with physician-diagnosed asthma and spirometry outcomes at age five.
The study included 1,050 infants who had dust samples collected at a mean age of 3.9 months. Researchers measured concentrations of dog allergen (Can f1), cat allergen (Fel d1), and endotoxin, then tracked asthma incidence and lung function development over time. By age five, 6.6% of participants were diagnosed with asthma.
Multivariable modeling revealed that higher concentrations of dog allergen Can f1 were significantly associated with a decreased risk of asthma (odds ratio 0.52; 95% CI 0.25–0.98). Children exposed to higher levels of Can f1 also demonstrated significantly improved lung function, reflected by higher FEV1 z-scores (β=0.23; 95% CI 0.06–0.40), independent of asthma status.
Importantly, the analysis identified gene–environment interactions between Can f1 exposure and polygenic risk scores for lung function. These findings suggest that genetic susceptibility may modify the benefits of early-life allergen exposure.
The results highlight the potential protective role of early exposure to dog-derived allergens in shaping respiratory outcomes. While prior studies have reported conflicting associations between allergen exposure and asthma, this longitudinal analysis provides evidence that controlled early exposure, particularly to Can f1, may support more favorable lung development in children.
The study underscores the importance of considering both environmental and genetic factors in understanding asthma risk, offering insight into early preventive strategies and potential avenues for personalized care in pediatric respiratory health.
Reference: McCoy J et al. Association of early-life dust allergens and endotoxin with childhood asthma and lung function: An analysis of the CHILD study. Abstract OA1265. ERS Congress, 26–30 September 2025.
