New research suggests babies who grow up around dogs may be less likely to develop childhood asthma but the same benefit isn’t seen with cats.Scientists in Canada studied more than a thousand children, collecting dust samples from their homes when the babies were just a few months old.They tested the samples for three common pet allergens.When the children turned five, doctors assessed them for asthma, measured their lung function, and checked blood samples for genetic risk factors.The findings? Babies exposed to higher levels of a dog allergen called Can f1 had a 48% lower risk of developing asthma.They also showed stronger lung function — even if they were genetically at higher risk.The researchers found no protective effect for babies exposed to the cat allergen Fel d1 or the bacterial endotoxin.“This suggests that early exposure to dog allergens could prevent sensitization, perhaps by altering the nasal microbiome – the mixture of microbes living inside the nose – or by some effect on the immune system, ” says Dr Jacob McCoy from The Hospital for Sick Children, Toronto.Asthma is one of the most common chronic conditions in children.Doctors say while treatments exist, understanding how to prevent it could make a big difference for families worldwide.Source: European Respiratory Society (ERS) CongressAuthor Affiliations: The Hospital for Sick Children.Sign up for our weekly HealthDay newsletter