Overview
- Published in June 2026, researchers from Karolinska Institutet used linked national registers to follow 30,277 Swedish children with asthma or airway allergy over 24 months and found no short-term link between household cat ownership and worse asthma outcomes.
- Measured outcome rates were similar between groups, with moderate-to-severe asthma at about 9.6% for cat-exposed children versus 10.1% for unexposed children and exacerbations at roughly 3.3% versus 3.5%.
- The study found no effect from the number, age, or sex of household cats and showed no consistent differences in lung function or asthma control in the subset with spirometry and control-test data.
- Authors warned key limits that could hide real risks: they lacked data on which allergens each child was sensitized to, the National Cat Register is new so some exposure may be misclassified, and follow-up so far covers only two years.
- Researchers say common community exposure to cat allergen and family selection against pets for highly allergic children could blur differences, and they plan longer follow-up and analyses by allergen sensitization to guide clinical advice for families.