Abstract
The determinants of respiratory symptoms were studied in an active workforce of insulation workers exposed to asbestos and synthetic mineral fibres. Responses to a mailed respiratory symptom questionnaire from 537 insulation workers without diagnosed asbestosis were analysed using logistic regression. Wheezing complaints and breathlessness were related primarily to current cigarette smoking and to symptoms suggesting an asthmatic predisposition antedating work in the trade. There was also evidence that these complaints were related to occupational exposure (estimated by number of hours worked in the trade) in subjects with prior airways hyperreactivity. An asthmatic predisposition antedating work in the trade was the major determinant of acute respiratory symptoms in the workplace. The effects of workplace exposures on respiratory symptoms may have been underestimated due to selective withdrawal from the active workforce and due to inaccuracies in the measure of exposure used.