Asthma and allergies: the "protective" effect of pets partly explained

People with asthma or allergies would prevent most of the time and spontaneously acquire a cat, which may partly explain the lower number of allergy seen in pet owners, suggests a study published in European " The Journal of Allergy and Clinical Immunology. "

Some studies have shown that children exposed early to a domestic cat or dog had a reduced risk of developing allergies or asthma risk later. To explain this, two opposing theories. In the first, the immune system of these children have been educated by early exposure to allergens. According to the second explanation would be based on the choice of families hereditary high risk of allergies not to adopt pets.

To resolve this issue, Cecilie Svan, University of Bergen (Norway) and his European colleagues, evaluated in 9812 children and adults in the European study "European Community Respiratory Health Survey", followed for 9 years, the link between the presence of asthma and allergies, and the choice to become or remain the owner of pets.

Their results indicate that children with asthma before the age of 5 years have revealed 40% less likely to care for a domestic cat between 5 and 15 years, compared to children without asthma. However, childhood asthma would not influence the decision of adults to acquire a pet, unless adults are themselves victims of asthma or allergy.

In fact, adults were less likely to become owners of a cat when they had at least three asthma symptoms, allergic symptoms or if they were taking asthma.

Adults already own a dog, have mostly kept the same pet. However, people with at least three asthma symptoms were more likely to part with their dog. The decision to separate from her pet due to an allergen risk was reported by 4.7% of study participants.

Selective avoidance acquisition of a cat has been observed in both children and adults as a result of the development of asthma or allergy. This avoidance behavior generates an apparently protective effect on childhood asthma.

However, avoidance behavior was not observed with either dogs or with domestic birds. Part of the preventive effect of domestic cats on asthma and allergies in children can be attributed therefore selective avoidance behavior, the authors conclude.