Exposure to pets and atopy-related diseases in the first 4 years of life

Background: It is still unclear how early-life exposure to pets is related to children's risk of developing atopy-related diseases. We estimated assoc iations between early-life exposure to pets and atopy-related diseases at 0 -4 years of life in a cohort of Norwegian children. Methods: A population-based cohort of 2531 children born in Oslo, Norway, w as followed from birth to the age of 4 years. Information on early-life exp osure to pets, a number of possible confounders, and atopy-related diseases was mainly collected by questionnaire. Results: In logistic regression analysis adjusting for potential confounder s, the odds ratio for being exposed to pets in early life (reference catego ry: not exposed) was, for bronchial obstruction at 0-2 years of life, 1.2 ( 95% confidence interval 0.9, 1.8); for asthma at the age of 4 years, 0.7 (0 .5, 1.1); for allergic rhinitis at the age of 4 years, 0.6 (0.4, 1.0); and for atopic eczema at 0-6 months of life, 0.7 (0.5, 0.9). Conclusions: The results indicate that early-life exposure to pets or lifes tyle factors associated with, exposure to pets reduce the risk of developin g atopy-related diseases in early childhood. However, these findings might also be explained by selection for keeping pets.