SENSITIZATION TO DUST MITES AS A DOMINANT RISK FACTOR FOR ASTHMA AMONG ADOLESCENTS LIVING IN CENTRAL VIRGINIA - MULTIPLE-REGRESSION ANALYSIS OF A POPULATION-BASED STUDY

Factors influencing asthma were investigated in a population of school children in central Virginia. A survey of 1,054 children in two middl e schools (one urban and one suburban) identified 135 students with sy mptoms suggestive of asthma. Eighty-eight symptomatic children and 123 control subjects were randomly selected for further evaluation by ski n testing using common indoor and outdoor allergens; serum assays for total IgE and specific IgE; dust samples assayed for mite (Der p 1 Der fl), cat (Fel d 1), and cockroach (Bla g 2) allergens; and provocatio n with histamine to test for bronchial hyperreactivity. Forty-eight of the children with symptoms responded to less than or equal to 3.9 mu mol of histamine and were considered to have asthma. Marginal analysis identified elevated total IgE and dust mite, cat, and cockroach sensi tization as significant risk factors for asthma. Using multiple regres sion, only dust mite sensitization was independently associated with a sthma (odds ratio = 6.6; p < 0.0001). Dust from 81% of the houses cont ained high levels of mite allergen (> 2 mu g/g), while similar to 40% of the children were exposed to cat and 17% were exposed to cockroach allergen. In this population, there was no significant association bet ween asthma and race, socioeconomic status, home smoking, sensitizatio n to outdoor allergens, or allergen concentration in the child's home. In an area where there is a high prevalence of asthma and most houses contain high concentrations of dust mite allergen, sensitization to t his allergen is the dominant risk factor for asthma defined as symptom atic bronchial hy perreactivity.