No Link Between Cat Ownership and Asthma Flare-Ups in Children, Swedish Registry Study Finds
核心洞察
A nationwide Swedish study of over 30,000 children with asthma (搜索) and allergies found no association between cat exposure and worse asthma outcomes, including exacerbations, severity, lung function, or asthma control.
Asthma (搜索) exacerbations occurred in 3.3% of cat-exposed children versus 3.5% of non-exposed children, while moderate-to-severe asthma affected 9.6% and 10.1%, respectively, with neither difference reaching statistical significance.
The findings challenge long-standing clinical advice that families with asthmatic children should avoid keeping cats, though researchers caution that individual clinical guidance remains essential.
A comprehensive Swedish registry study has found that children with diagnosed asthma (搜索) and allergies who live with one or more cats do not experience worse asthma outcomes than children without cats at home, challenging long-standing clinical assumptions about pet ownership in families managing childhood asthma.
The study, published in Frontiers in Allergy and conducted by researchers at Karolinska Institutet, analyzed data from over 30,000 children aged 4 to 17 across Sweden, following them over a two-year period from 2023 to 2024.
"Clinical advice always needs to be tailored to the individual, and our study can contribute to the evidence base in discussions with families about pets and asthma (搜索)," said Catarina Almqvist Malmros, professor at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, and paediatrician at Astrid Lindgren Children's Hospital.
No Significant Differences Across Key Asthma (搜索) Outcomes
The researchers examined multiple asthma (搜索)-related endpoints, including exacerbations leading to emergency or unplanned hospital visits, asthma severity based on medication use, asthma control test (ACT) scores, and lung function measured by forced expiratory volume in one second (FEV1).
Asthma (搜索) exacerbations occurred in 3.3% of the cat-exposed group compared to 3.5% of the non-exposed group. Moderate-to-severe asthma—defined as requiring more than one controller medication such as a combination of inhaled corticosteroids (搜索) (ICS) with leukotriene receptor antagonists (搜索) (LTRA) or long-acting beta-2 agonists (搜索) (LABA), or prescription of theophylline or biologics—affected 9.6% of cat-exposed children and 10.1% of non-exposed children. Neither difference reached statistical significance.
In a subset of 1,428 children with both ACT and FEV1 data, including 97 who were cat-exposed, uncontrolled asthma (搜索) was reported in 16.5% of the cat-exposed group versus 22.3% of the non-exposed group—again, not a statistically significant difference. ACT and FEV1 z-score distributions, mean FEV1 z-scores, and FEV1/FVC ratios were comparable between groups, indicating that cat exposure did not influence lung function or airway limitation.
Cat Characteristics Show No Influence
Within the cat-exposed group, the researchers found that the number of cats in the home, as well as the age or sex of the cat, could not be linked to differences in asthma (搜索) outcomes. Additionally, excluding children with dog exposure from the analysis yielded similar null findings.
"We found no evidence that living with cats worsens asthma (搜索) in children who already have asthma and allergies," said Resthie R. Putri, postdoctoral researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. "Unfortunately, however, we had no information on the specific allergies the children had, so we do not know whether they were allergic to cats or not."
Study Strengths and Limitations
The study drew from an initial cohort of 32,010 children with persistent asthma (搜索) and allergy, of whom 1,733 were excluded due to migration, death, or missing parental data, leaving a final study population of 30,277 children with a median age of 9.5 years. Of these, 38.6% were female and 9.4% were exposed to cats.
Cat exposure was defined as any recorded parental cat ownership during 2023, with data obtained from the Swedish National Cat Register and combined with information from several Swedish health and quality registers. Asthma (搜索) and allergic rhinitis (搜索) diagnoses were confirmed using validated algorithms based on diagnosis and medication codes.
The researchers acknowledged several important limitations. The Swedish National Cat Register was established relatively recently, meaning some cat exposure may not have been captured. The study also lacked data on allergen-specific IgE sensitization, patterns of mono- versus polysensitization, prior cat ownership, duration of ownership, and whether cats were kept primarily indoors or outdoors. Furthermore, the researchers could not rule out the possibility that families with children suffering from more severe allergies may have chosen not to keep a cat.
The authors also cautioned that these findings apply specifically to children with established asthma (搜索) and airway allergy and should not be generalized to non-allergic asthma. Differences in pet-keeping practices, climate, and environmental exposures between countries may limit the applicability of the results to other contexts. Importantly, the absence of an association with cats should not be assumed to hold for all furry animals, as previous studies have reported different relationships between dog exposure and asthma outcomes.