Decreased prevalence of sensitization to cats with high exposure to cat allergen

We investigated the relationship between current exposure to cat allergen a nd sensitization to cats. A questionnaire was administered and skin prick t esting and home visits for collection of dust samples (Fel d 1; ELISA) were performed in 2502 adults (mean age, 31.8 years; age range, 18-58 years; 12 51 women). The results for Fel d 1 in relation to sensitization to cats wer e analyzed for 10 deciles of cat allergen exposure (cut points [mug/g]: 0.0 5, 0.34, 0.48, 0.72, 1.13, 1.92, 7.2, 44, 151). The prevalence of sensitiza tion to cat was significantly decreased in the lowest and the highest expos ure groups. In the multivariate regression analysis (age, sex, socioeconomi c status, and current smoking being adjusted for), the risk of sensitizatio n to cats was significantly increased with medium exposure to Fel d 1 (3rd centile, OR 2.3, 95% CI 1.2-4.4, P = .01; 4th centile, OR 2.1, 95% CI 1.1-4 .0, P = .03; 5th centile, OR 2.2, 95% CI 1.2-4.3, P = .04, 6th centile, OR 2.5, 95% CI 1.3-4.9, P = .005). These results indicate that the prevalence of sensitization to cat is decreased in the lowest and highest cat allergen exposure groups.