Environmental allergens and asthma in urban elementary schools

Background: Asthma in school children is rising, and indoor allergens are very common triggers of asthma attacks; however, the risk of the school environment on asthma has not been well studied. Objective: To determine the presence and the levels of common aeroallergens in schools, where asthma prevalence rates are high. Methods: Settled dust samples were collected from 12 Baltimore City public elementary schools, and they were analyzed for the following allergens: cockroaches (Bla g 1/2), dust mites (Der f 1/p 1), dog (Can f 1), cat (Fel d 1), and mouse (Mus m 1). School asthma prevalence rates were correlated with allergen levels, and association between allergen levels and other risk factors present in the schools' environment was examined. Results: The mean and range levels were 1.49 U/g (0 to 8) for Bla g 1/2; 0.38 mug/g (0 to 11.9) for the Der f 1/p 1; 1.44 mug/g (0.1 to 9.6) for Can f 1; 1.66 mug/g (0.2 to 12) for Fel d 1; and 6.24 mug/g (0.3 to 118.3) for Mus m 1. Dust mite, cat and dog allergens were significantly in rooms with carpet and/or area rugs, compared to rooms with bare floors (P < 0.05). Asthma prevalence rates varied from 11.9 to 20.8% between schools and positively correlation with the mean levels of Bla g 1/2 in the schools (P = 0.001) Conclusions: Common allergens that are known to trigger asthma were detected in all school environments, where asthma prevalence rates were high. However, the overall allergen levels were low, indicating that other factors, including exposures in the homes of asthmatic patients, may have more relevance to sensitization and symptoms than school exposures.