Pet ownership is associated with increased risk of non-atopic asthma and reduced risk of atopy in childhood: Findings from a UK birth cohort

BACKGROUND: Studies have shown an inverse association of pet ownership with allergy but inconclusive findings for asthma.

OBJECTIVE: To investigate whether pet ownership during pregnancy and childhood was associated with asthma and atopy at age 7 years in a UK population-based birth cohort.

METHODS: Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) were used to investigate associations of pet ownership at six time-points from pregnancy to age 7 years with asthma, atopy (grass, house-dust mite, and cat skin prick test) and atopic versus non-atopic asthma at age 7 years using logistic regression models adjusted for child's sex, maternal history of asthma/atopy, maternal smoking during pregnancy and family adversity.

RESULTS: 3,768 children had complete data on pet ownership, asthma and atopy. Compared with non-ownership, continuous ownership of any pet (before and after age 3 years) was associated with 52% lower odds of atopic asthma (odds ratio [OR] 0.48, 95% CI 0.34-0.68). Pet ownership tended to be associated with increased risk of non-atopic asthma, particularly rabbits (OR 1.61, 1.04-2.51) and rodents (OR 1.86, 1.15-3.01), comparing continuous versus non-ownership. Pet ownership was consistently associated with lower odds of sensitization to grass, house-dust mite and cat allergens, but rodent ownership was associated with higher odds of sensitization to rodent allergen. Differential effects of pet ownership on atopic versus non-atopic asthma were evident for all pet types.

CONCLUSIONS: Pet ownership during pregnancy and childhood in this birth cohort was consistently associated with a reduced risk of aeroallergen sensitization and atopic asthma at age 7 years, but tended to be associated (particularly for rabbits and rodents) with an increased risk of non-atopic asthma.

CLINICAL RELEVANCE: The opposing effects on atopy versus non-atopic asthma might be considered by parents when they are deciding whether to acquire a pet. This article is protected by copyright. All rights reserved.