Asbestos Workers in Singapore

A survey of 114 employees exposed to asbestos in a Singapore plant revealed no subjects with major disability or advanced radiographic changes. Basal crepitations in nine subjects were found to have no association with indices of chronic bronchitis such as history of cough and sputum, productive cough upon request, and smoking. These indices tended to be related to the presence of other adventitious sounds, recorded in 14 patients. Ventilatory capacity changes occurred in the direction of a restrictive ventilatory defect in the group with crepitations, and an obstructive defect in the group with other adventitious sounds. Simple clinical and functional studies can be used to define three groups within the total population of exposed asbestos workers: (1) normal (2) presumptive diagnosis of chronic bronchitis, and (3) presumptive diagnosis of mild respiratory abnormality consistent with “mild” or “early” asbestosis, deserving at least close surveillance.