For many years, researchers believed that exposure to cat allergens increased a child’s risk of developing asthma. More recent research, however, has suggested a more nuanced relationship. A study conducted by the National Institutes of Health and published in The Lancet (2002;360(9335):781–782) reported that early-life exposure to cats may be linked with a lower risk of asthma in children—except in cases where the child’s mother has asthma.
The study followed 448 children with a family history of allergic disease. Researchers assessed exposure to cats by interviewing caregivers and by measuring cat dander levels in the home environment.
Among children whose mothers did not have asthma, exposure to cats was associated with a 40% lower likelihood of persistent wheezing compared with children who were not exposed to cats. In contrast, children whose mothers had asthma showed a different pattern. In this group, exposure to cats was linked with a higher risk of persistent wheezing that increased over time. By the third year of life, the risk of wheezing had doubled, and by the fifth year, it had more than tripled.
These findings suggest that early environmental exposures may influence respiratory outcomes differently depending on underlying genetic or familial risk. While cat exposure may be linked with reduced asthma-related symptoms in some children, maternal asthma appears to modify this relationship in an important way.
