Lung function and exposure to asbestos among vehicle mechanics

Vehicle mechanics (n = 99) exposed to asbestos (annual median value 0.08 f/ml), and local controls (n = 83) not occupationally exposed to asbestos were studied with regard to symptoms and pulmonary function. The inclusion criteria to participate in this study was an age of at least 40 years with no known exposure to lung irritating agents, and for the exposed subjects, more than 15 years occupational exposure to asbestos with at least 20 years from the first exposure. The subjects were studied during identical conditions by means of dynamic and static spirometry, single breath wash-out with nitrogen (N2) and carbon monoxide (CO). The median for cumulative exposure of asbestos during the entire work life among the studied mechanics was 2.3 f*y/ml. The mechanics had reduced transfer factor (TLCO), after adjustment for age, height, and smoking category. A significant dose-response relationship was noted between the cumulative exposure of asbestos and CV%. The findings suggest a slight influence of small airways and alveoli. The evaluation of the prognostic significance of this requires a longitudinal study.