Dog Ownership is Associated with Less Wheezing among High-Risk Infants During the First Year of Life

RATIONALE: Pet ownership has been reported to influence allergic sensitization and asthma in childhood. METHODS: In a birth cohort of 881 one year old infants born to atopic parents participating in the Cincinnati Children Allergy and Air Pollution Study, we collected house dust samples from the living area of 367 infants. Der f 1, Fel d1, Bla g1 were analyzed by monoclonal ELISA, dog and Alternaria antigen by competitive inhibition assay, and endotoxin by Limulus assay. Clinical assessments and skin prick testing were performed with 15 aeroallergens, milk and egg. RESULTS: Geometric mean levels/g of dust sample were: 0.32 μg Der f1; 2.15 μg Fel d1; 0.34 IU Bla g1; 17.4 μg of dog allergen & 39.4 μg Alternaria. Wheezing (≥2 episodes in past 12 months) was less likely if dogs were present in the home (40% of households); prevalence was 18%, 26% if a dog was present versus absent (X 2 = 3.5, p=0.06). Although dog ownership was significantly and positively associated with the highest level of endotoxin or > 140 EU/mg dust (X 2 = 4.8; p=0.03), logistic regression showed that high (>140 EU/mg) endotoxin exposure (versus ≤ 140), controlling for the presence of dog was positively but non-significantly related to wheezing [OR=1.4 (95% CI=0.8, 2.4)]; prevalence was 26% and 21%, respectively. No significant relationship was found between level of endotoxin exposure or pet ownership on prevalence of cutaneous reactivity to aeroallergens. CONCLUSION: Exposure to dog is associated with less wheezing during the first year of life.