BACKGROUND: Exposure to high levels of cat allergen might prevent sensitization. OBJECTIVE: We sought to measure the incidence of allergic sensitization among schoolchildren living in a dust mite- and cockroach-free environment and the associated risk factors. METHODS: In 1996, a longitudinal cohort was established in northern Sweden, including 2454 @entity1 aged 7 to 8 years. @entity1 were skin tested, and the testing was repeated 4 years later. Questionnaires were completed yearly. Participation was 88% both in 1996 and 2000. RESULTS: The prevalence of positive skin test results increased from 20.6% at age 7 and 8 years to 30.4% at age 11 and 12 years, a cumulative incidence of 13.8%, and was significantly higher among @entity1 . The incidence was highest for cat (6.0%), timothy grass (5.9%), @entity235 (4.9%), and birch (3.6%). A family history of @entity566 was the major risk factor for both a positive skin test response at age 7 and 8 years (odds ratio [OR], 1.69; 95% CI, 1.36-2.10) and for development of a positive skin test response over the next 4 years (OR, 1.67; 95% CI, 1.23-2.28). A significant inverse association between cat and @entity235 ownership and the prevalence of type 1 @entity566 was found, particularly for those @entity1 who had lived with a cat both before age 7 and 8 years and during the next 4 years (OR, 0.44; 95% CI, 0.31-0.61). A similar pattern, although not significant, was found for incident cases. CONCLUSION: The high incidence of type 1 @entity566 at this age was similar to reports from communities with mite and cockroach allergen. Despite cat and @entity235 being the most common allergens of sensitization, keeping these animals at home was not associated with an increased risk for sensitization.

Four-year incidence of allergic sensitization among schoolchildren in a community where @entity566 to cat and XXXX dominates sensitization: report from the Obstructive Lung Disease in Northern Sweden Study Group.

@entity1 :: ('9606', 'Species') :: ['children', 'Children', 'boys'] @entity566 :: ('MESH:D006967', 'Disease') :: ['allergy'] @entity235 :: ('9615', 'Species') :: ['dog']
@entity235 :: (9615,Species) :: ['dog']
