[Pilot study of the prevalence of a hyperreactive bronchial system in various occupationally-induced lung diseases]

A pilot study was performed to assess the prevalence of hyperreactive bronchial system (HBS) in various occupational lung diseases. 204 patient records were evaluated with the following diagnosis: Allergic rhinitis: (N = 25, 12%), allergic bronchial asthma (N = 70, 34%), toxic asthma (N = 22, 11%), silicosis (N = 12, 6%), asbestosis (N = 15, 7%), farmer's lung (N = 12, 6%), chronic unspecific respiratory syndrome (N = 48, 24%). In each case an inhalative methacholine test (MCHT) was performed. HBS was considered to be present whenever there was a resistance increase of more than 100% of the baseline values. The prevalence of HBS varied between 50% (asbestosis) and 77% (toxic asthma); the average was 68%. Allergic diseases showed a higher prevalence of 71% in comparison to nonallergic diseases with 65%. Patients with silicosis or asbestosis and without additional chronic bronchitis or emphysema demonstrate a "normal" prevalence of HBS of 11%. Age, gender, smoking, alcohol, family history of allergy and repeated bronchitis, the number of eosinophils in the blood. IgE concentration in serum showed no significant association with an increased prevalence of HBS. The coincidence of anamnestically affirmed or denied bronchial hypersensitivity to environmental factors, and the positive or negative result of the MCHT test, was relatively low, being only 43% in case of a "positive" test and 17% in case of a "negative" test.(ABSTRACT TRUNCATED AT 250 WORDS)