Reducing exposure to cats may therefore benefit all people with allergies.
For the study, 1,884 people were tested for IgE sensitisation to four major allergens: cat, house dust mite, mould and timothy grass. Additionally, samples of mattress dust were collected from 3,119 homes. The samples were examined for the presence of dust mites and cat allergens.
Each participant also completed a questionnaire on smoking status, cat ownership and any childhood illnesses. Overall,
28 per cent of the individuals were sensitive to at least one allergen.
Although only 157 of the participants were sensitive to cats, people sensitive to any allergen had high bronchial responsiveness to levels of cat allergen of 8µg per gram of mattress dust.
The difference between low and high exposure to cat allergen in relation to bronchial responsiveness was almost as high as that noted between individuals with and without asthma.
The researchers suggested that cat allergen exposure or owning a cat could be a proxy for exposure to endotoxin. This is a known immune stimulant associated with asthmatic symptoms and is found in higher concentrations in cat owners' homes.
Am J Respir Crit Care Med 2007; 176: 20-26