For years, parents of children with asthma and allergies have often been advised to avoid keeping cats at home due to concerns that pet allergens could worsen breathing problems. However, a new large-scale study from Sweden suggests that living with a cat may not increase asthma severity or trigger more asthma attacks in children already diagnosed with asthma and allergies.

The findings, published in the journal Frontiers in Allergy, challenge a common belief about pet ownership and asthma management and may offer reassurance to families who share their homes with cats.

The study was led by Dr. Resthie R. Putri and colleagues from the Karolinska Institutet in Stockholm. Researchers analyzed data from 30,277 children aged between 4 and 17 years who had validated diagnoses of both asthma and allergies. Using Swedish national health registers, the team examined whether cat exposure affected asthma severity, asthma control, lung function or the risk of asthma exacerbations.

Among the children included in the study, 2,862, or 9.4 percent, lived in households with cats.

When researchers compared children exposed to cats with those who were not, they found little difference in asthma outcomes. Moderate-to-severe asthma was initially present at similar rates in both groups, and the likelihood of experiencing asthma exacerbations during the study period was nearly identical.

Asthma attacks occurred in 3.3 percent of cat-exposed children compared with 3.5 percent of children who did not live with cats. Similarly, moderate-to-severe asthma was reported in 9.6 percent of cat-exposed children and 10.1 percent of non-exposed children.

To gain a deeper understanding of asthma control, researchers also evaluated a subgroup of 1,428 children using the Asthma Control Test (ACT) and lung function measurements, including forced expiratory volume in one second (FEV1). The analysis found no significant differences between children living with cats and those without cat exposure.

The study also explored whether factors such as the number of cats in the household, the cat's age or its sex influenced asthma outcomes. Researchers found no evidence that any of these factors affected asthma severity, lung function or symptom control.

Summarizing the findings, Dr. Putri said the study provides important real-world evidence from a nationwide population of children with asthma and allergies.

“Here we show in a nationwide cohort of children in Sweden with asthma and allergies that children living with a cat had similar asthma severity, exacerbation, asthma control and lung function to children living without cats in the short term,” she said.

Experts caution that the findings should not be interpreted to mean that cat allergies do not exist or that all children with asthma will respond similarly to pet exposure. Individual allergic sensitivities can vary significantly, and some children may still experience symptoms triggered by cat allergens.

However, the study suggests that, at a population level, living with a cat does not appear to worsen asthma outcomes among children who already have asthma and allergies.

Researchers say further studies are needed to understand the long-term impact of cat exposure and whether the findings apply to children in other countries and environments.

The results add to an ongoing scientific debate about the relationship between pets, allergies and respiratory health, while offering reassurance that cat ownership may not necessarily lead to poorer asthma control in children.