The effects of pet exposure and parental atopy on respiratory symptoms were investigated in 12,910 children residing in twelve districts of northeast China. Responses to a self-administered questionnaire completed by parents of children were used to ascertain children with persistent cough, persistent phlegm, doctor-diagnosed asthma, current asthma and current wheeze. Exposure to animals during pregnancy was positively associated with doctor-diagnosed asthma [adjusted odds ratio (ORs), 1.86; 95% confidence interval (CI) 1.35-2.57], current asthma (adjusted OR, 3.06; 95% CI, 1.95-4.81) and asthma-related symptoms. Pet exposure in the first year of life and currently having animals in household were also related to a significantly higher prevalence of doctor-diagnosed asthma and asthma-related symptoms in these children. Associations with respiratory symptoms strengthened with higher levels of animal exposure. Parental atopy increased the risk of asthma diagnosis (OR, 3.49; 95%CI, 2.84-4.30), current asthma (OR, 3.94; 95%CI, 2.81-5.54) and asthma-related symptoms. There was an interaction between parental atopy and pet exposure in persistent phlegm, but not in doctor-diagnosed asthma. We conclude that pet keeping and parental atopy increased the risk of respiratory symptoms in children. Parental atopy did modify the effect of pet exposure on persistent phlegm but not on doctor-diagnosed asthma.
Practical implications: The relationship between exposure to animals and allergic respiratory diseases in childhood is controversial. Inconsistent with other cross-sectional studies mostly conducted in industrialized countries, our study indicates that exposure to animals may increase the occurrence of respiratory symptoms and diseases in children, and the associations with respiratory symptoms strengthened with higher levels of animal exposure parental atopy did modify the effect of pet exposure on persistent phlegm but not on doctor-diagnosed asthma. These findings support the view that measures should be taken to reduce animal exposure for children in China.