Pet Ownership Increases the Exhaled Nitric Oxide and Asthma Severity in Children With Atopic Asthma.

Exposure to pets can trigger symptoms in asthmatic children sensitized to pets. However, little is known about the association between pet ownership and asthma morbidity in children who are not sensitized to pets. We aimed to investigate the effect of pets on lung function, airway inflammation, and morbidity in children with asthma, and to determine whether the effect of exposure to pets vary based on pet sensitization status. A total of 975 asthmatic children, aged 5-15 years, were enrolled in the Korean Childhood Asthma Study. Pet ownership and asthma morbidity were evaluated by questionnaires or pediatrician evaluations. Pulmonary function, fractional exhaled nitric oxide (FeNO), and atopic status were assessed. FeNO levels were significantly higher in children with pets than in those without pets. Pet ownership significantly increased FeNO levels in atopic asthmatic children, irrespective of pet sensitization status. In children sensitized to pets, the geometric mean was 46.6 (range of 1 standard deviation, 26.9-81.5) for those with pets vs. 27.2 (13.8-53.6) for those without pets (P < 0.001). In children without sensitization to pets, the geometric mean was 37.3 (15.0-53.6) for pet owners vs. 25.2 (12.9-49.2) for non-owners (P = 0.014). The multiple regression analysis also revealed that pet ownership was significantly associated with increased FeNO levels and asthma severity in atopic asthmatic children. Pet ownership increased the FeNO levels and asthma severity, regardless of pet sensitization status, in children with atopic asthma. Exposure to pets could increase airway inflammation and disease severity even in atopic asthmatic children who are not sensitized to pets.