Dogs (But Not Cats) May Protect Against Childhood Asthma, Study Says

Key TakeawaysGrowing up with a dog might protect against childhood asthmaBabies in a home with a dog had a 48% lower risk of asthma by age 5, and better lung functionNo similar protection was found in kids growing up with cats.MONDAY, Sept. 29, 2025 (HealthDay News) — Babies who grow up around dogs might be less likely to develop childhood asthma, a new study says.However, they don’t get the same protection from growing up around cats, according to findings presented Sunday in Amsterdam at a meeting of the European Respiratory Society.“We found that, while cat allergens showed no association, exposure to dog allergens was linked to improved lung function and a reduced risk of asthma,” researcher Jacob McCoy said in a news release. He’s a graduate student at the Hospital for Sick Children in Toronto, Canada.For the study, researchers analyzed samples of dust taken from 1,050 Canadian babies’ homes when they were 3 to 4 months old.The dust samples were tested for three potential allergens: Can f1, a protein shed in dog skin and saliva; Fel d1, a protein shed in cat skin and saliva; and endotoxin, a protein found on the surface of bacteria.The team then retested the children for asthma at age 5. Their lung function was measured by the amount of air they could exhale in one second after a deep inhale.Babies exposed to higher levels of the dog allergen had a 48% lower risk of developing asthma by age 5, results showed. These children also had better lung function.Further, researchers found this protective effect was even stronger in babies with a higher genetic risk for asthma and allergies.No similar benefits were found growing up around either the cat allergen or the bacterial allergen.“We don’t know why this happens; however, we do know that once a person becomes sensitive to dog allergens, they can make asthma symptoms worse,” McCoy said.“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,” he added.More research is needed to understand this link between early-life exposure to dog allergens and potential protection from asthma, McCoy said.Dr. Erol Gaillard, chair of the European Respiratory Society’s expert group on pediatric allergy and asthma, found reason for hope in the findings.“Asthma is the most common long-term condition among children and young people and is also one of the main reasons for children being admitted to hospital for emergency treatment,” he said in a news release.“Although there are good treatments that can reduce or stop asthma symptoms, we also want to reduce risk factors to try to prevent asthma,” Gaillard continued. “This is potentially good news for families with pet dogs; however, we need to know more about this link and how living with pets affects children’s developing lungs in the longer term.”Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.More informationThe Cleveland Clinic has more on pets and allergies.SOURCE: European Respiratory Society, news release, Sept. 26, 2025.What This Means For YouHaving a dog in your house might help protect your newborn against childhood asthma..Sign up for our weekly HealthDay newsletter