Dog Ownership in Early Life Increased the Risk of Nonatopic Asthma in Children

Abstract

<b><i>Background:</i></b> It is still debatable whether dog ownership during early childhood is a risk factor for the development of allergic diseases. <b><i>Objective:</i></b> We investigated the association of dog ownership in early life with sensitization and asthma in childhood. <b><i>Methods:</i></b> Data from the Cohort for Childhood Origin of Asthma and Allergic diseases were used to investigate the association between dog ownership at any time from pregnancy to 1 year of age and sensitization to aeroallergens at 3 and 7 years old, bronchial hyperresponsiveness (BHR), and asthma at 7 years old. We analyzed the cytokine levels in cord blood (CB) and indoor environmental measurement concentrations in the mother’s residence obtained at 36 weeks of pregnancy. <b><i>Results:</i></b> Sensitization to dogs at age 3 and 7 did not differ between dog ownership and nonownership, but dog ownership during early life decreased the risk of sensitization to aeroallergens at age 7 (aOR = 0.44, 95% CI 0.21–0.90). Dog ownership significantly increased the risk of nonatopic BHR (aOR = 2.86; 95% CI 1.32–6.21). In addition, dog ownership was associated with asthma, especially nonatopic asthma at 7 years old (aOR = 2.73, 95% CI 1.02–7.32; aOR = 7.05, 95% CI 1.85–26.90, respectively). There were no significant differences in the concentrations of IL-13 or interferon-γ in CB or indoor environmental measurements according to dog ownership during pregnancy. <b><i>Conclusion:</i></b> Early-life dog exposure in this birth cohort has been shown to reduce atopy but increase the risk of nonatopic BHR and nonatopic asthma at 7 years old.