INFANTS exposed to higher levels of dog allergen in household dust were less likely to develop asthma by the age of 5 years and showed improved lung function, according to findings from the CHILD cohort study presented at the European Respiratory Society (ERS) Congress 2025. The results highlight a complex gene-environment interaction that may reshape understanding of early-life asthma risk factors.
Dog allergen exposure improves childhood lung function
Researchers analysed dust samples collected from the homes of 1,050 infants, with a mean age of 3.9 months, and tracked asthma diagnoses and spirometry outcomes through age 5. The team focused on common indoor allergens, including Can f1 (dog), Fel d1 (cat), and endotoxin. In adjusted multivariable models, higher Can f1 levels were associated with a nearly 50% reduction in asthma risk (odds ratio: 0.52, 95% CI: 0.25–0.98). Children exposed to high Can f1 also demonstrated significantly higher FEV1 z-scores (β=0.23, 95% CI: 0.06–0.40), regardless of whether they developed asthma.
Gene-environment interactions shape asthma outcomes
Beyond direct associations, the study identified a significant interaction between Can f1 exposure and polygenic scores for asthma risk. While early allergen exposure conferred protection in the overall cohort, genetic background influenced the strength and direction of its effects on lung function (interaction β=-0.14, 95% CI: -0.32–0.03). These findings emphasise the importance of personalised approaches in asthma prevention, integrating both environmental exposures and genetic susceptibility.
Asthma prevention insights from early-life exposures
This study provides some of the strongest evidence to date that dog allergen exposure in infancy may protect against asthma development and support healthier lung function in early childhood. Researchers note that while replication is needed in other cohorts, the results may inform public health strategies and early interventions aimed at modifying asthma risk.
If validated, these insights could help clinicians refine prevention recommendations by considering not only allergen exposure but also genetic risk profiles.
Reference
Nanishi M 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, 27 September-1 October, 2025.
