Growing up with dogs is linked to a lower risk of asthma, especially if the dogs are female, a new study shows. However, the researchers found no relation between ‘allergy friendly’ breeds and a lower risk of asthma.
Earlier studies have demonstrated a link between growing up with dogs and a lower risk of childhood asthma, but it has not been known whether this association is modified by dog characteristics. In this new study, the researchers have interrogated how variables such as sex, breed, number of dogs or size of dog are associated with the risk of asthma and allergy amongst children raised in a home with a dog during their first year of life.
“The sex of the dog can affect the amount of allergens released, and we know that uncastrated male dogs express more of a particular allergen than castrated dogs and female dogs,” says Tove Fall, Senior Lecturer at the Department of Medical Sciences — Molecular Epidemiology at Uppsala University, who led the study with Professor Catarina Almqvist Malmros at Karolinska Institutet. “Moreover, some breeds are described anecdotally as ‘hypoallergenic’ or ‘allergy friendly’ and are said to be more suitable for people with allergies, but there is no scientific evidence for this.”
The study included all children born in Sweden from 1 January 2001 to 31 December 2004 who had a dog in their home for the first year of life (23,600 individuals). Data from the Swedish population and health data registries were linked anonymously to two dog-owner registries from the Swedish Board of Agriculture and the Swedish Kennel Club. The dogs were classified by sex, breed, number, size and alleged ‘hypoallergenicity.’