That Darn Cat. Allergen That Is.

Diane Gold
Brigham and Women's Hospital
R01AI/ES35786

Background: Exposure to cats, or more precisely, exposure to the natural allergens from their skin and hair, has been implicated in the development of asthma in children. Asthma is a serious illness affecting approximately five million children in the U.S. and accounting for more missed school days than any other children's disease resulting in staggering amounts of lost work productivity for parents who must stay home with sick children. Asthma is also a very expensive illness with estimates as high as $11 billion/year in health care costs. Some studies have shown a positive correlation for asthma incidence and exposure to cat allergens while others have shown no correlation. These investigators performed an epidemiologic study with 448 children and their families to study the associations of cat and dog allergens, maternal and paternal history of allergies, and asthma development in these children.

Advance: Supported jointly by NIEHS and NIAID, the research team determined that among children whose mothers had no history of asthma, exposure to cat allergens at 2-3 months of age was associated with a 40% reduced risk of wheezing, a symptom of asthma, between age 1 and 5. However, among children whose mothers did have a history of asthma, similar exposure was associated with an increased risk of wheezing at or after 3 years of age. In these children, exposure to cat allergen at 2-3 months of age was associated with a 2.4-fold increased risk of wheezing at 3 years of age. This risk increased at ages 4 and 5. There was no association of wheezing with exposure to dog allergens and the father's asthma/allergy status had no effect.

Implication: These findings suggest that maternal history of asthma affects the relationship between exposure to cat allergen and wheezing among children with a parental history of allergy. The data suggest that women with a history asthma should avoid owning cats to protect their young children from developing asthma.

Citation: Celedon JC, Litonjua AA, Ryan L, Platts-Mills T, Weiss ST, Gold DR. Exposure to cat allergen, maternal history of asthma, and wheezing in first 5 years of life. Lancet. 2002 Sep 7;360(9335):781-2.