Pet-keeping in early childhood and airway, nose and skin symptoms later in life

Background: It is discussed whether exposure to pets during childhood is a risk or a protective factor for sensitization and allergic symptoms. The aim of this study was to investigate the association between pet-keeping at time of birth and allergic symptoms in airways, nose and skin among young children in Sweden. Methods: A questionnaire was sent to the parents of 14 077 children (1-6 years), the focus being on allergic symptoms, home environment and other background factors including pet-keeping and avoidance behaviour. The response rate was 79%. Results: Almost one-tenth of the population had got rid of pets because of allergy in the family, and 27.3% reported 'avoidance' behaviour towards pets. In a cross-sectional analysis current pet-keeping was 'protective', but this may be due to the fact that people avoid exposing their child to something that they believe is a risk factor for allergies. Pet-keeping at the time of birth was associated with 'wheezing', 'asthma' and 'rhinitis on pet-exposure' later in life for children from families with an 'avoidance' behaviour, and was not 'protective' for other children. There was also an indication of a dose-response relationship between the number of types of furred pets at time of birth and later symptoms in analyses adjusted for avoidance behaviour or current pet-keeping. Conclusion: The distribution of pet-keeping in the population is largely explained by avoidance behaviour, meaning that those who have pets mainly are those who can stand them, indicating a 'healthy pet-keeping effect'.