Effects of pet exposure in the first year of life on respiratory and allergic symptoms in 7-yr-old children. The SIDRIA-2 study

The effects of pet exposure on the development of respiratory symptoms have recently been the matter of vivid discussion. Our objective was to determine the effects of exposure to cat or dog in the first year of life on subsequent respiratory/allergic symptoms in children in a large Italian multicentre study. As part of the SIDRIA-2 Study (Studi Italiani sui Disturbi Respiratori dell'Infanzia e l'Ambiente 2002), the parents of 20016 children (median age 7 yr) provided information on indoor exposures at different times in life and respiratory/allergic symptoms through questionnaires. Logistic regression analyses were performed taking into account cat or dog exposure at different times in life and adjusting for the presence of the other pet, mould exposure, gender, age, parental education, maternal smoking during the first year of life, current passive smoking, family history of asthma/rhinitis/eczema and other potential confounders. Neither significant effects of dog exposure in the first year of life nor in other periods were found on respiratory/allergic symptoms after adjusting for the other covariates. Cat exposure in the first year of life was significantly and independently associated with current wheezing [OR (95% CI) 1.88 (1.33-2.68), p < 0.001] and current asthma [1.74 (1.10-2.78), p < 0.05] and border-line associated with current rhinoconjunctivitis [1.43 (0.97-2.11), p = 0.07]. No other effects of cat exposure were found on respiratory/allergic symptoms. Cat, but not dog, exposure in the first year of life is an independent risk factor for current wheezing, current asthma and current rhinoconjunctivitis at the age of 7.