Relationships between atopy and lung function: results from a sample of one hundred medical students in Japan.

Abstract

The prevalence of allergic diseases has been increasing dramatically and several studies have shown that atopy is related to asthmatic symptoms and bronchial hyperresponsiveness. To observe the relationships between atopic status and asthmatic predisposition (obstructive change in lung function) in apparently healthy young adults in Japan. A sample of 100 healthy Japanese medical students were subjected to a skin prick test for 11 common aeroallergens and food allergens, and their spirometric lung function was measured. Surprisingly, 90% of them showed a positive prick test result for at least one of the 11 allergens tested, and 59% of them showed allergic responses to more than three allergens. The positive rate for Dermatophagoidesfarinae (Der) was the highest (71.0%), followed by house dust (57.0%), Dactylois gloinerata (42.0%), Cryptomeria gromerata (Cry) (40.0%), and cat fur (39.0%). Furthermore, there was no statistical difference in the positive rates for Der and Cry between groups with and without either the present illness or past history of any of the three major allergic diseases: bronchial asthma (BA), atopic dermatitis (AD), or allergic rhinitis (AR). Compared with the positive rates for these aeroallergens, those for food allergens were much lower (4% to 9%). Several lung function parameters, including the levels of FEV1% and %V50 which reflect obstructive pulmonary changes, showed significant negative correlation to the number of skin prick test-positive allergens. The same correlation was observed for groups without either the present illness or past history of BA. These data suggest that those who are multi-allergic tend to feature subclinical asthma-like changes in their lung functions. Further studies are needed to determine whether this multi-allergic status can lead to future onset of asthma or other allergic diseases.