Factor analysis of clinical data from asbestos workers: implications for diagnosis and screening.

Clinical data from 624 asbestos exposed workers were analysed by factor analysis. Fifteen clinical variables were found to reflect several underlying factors: "obstruction," "interstitial disorder," "x ray change," "air tapping," and "age/exposure." Scoring individual subjects along these axes can facilitate identifying early cases and avoiding false diagnosis. The analysis suggests that screening should be multimodal and that radiographic abnormality need not imply physiological impairment.