Association between exposure to asbestos and pleural effusion. Results from a questionnaire study of 31,000 persons.

All visitors to a general health survey in 1979, 17,140 men and 14,371 women, completed a questionnaire on smoking habits, exposure to asbestos, silica and welding fumes, and diseases such as pleural effusion, pneumonia, cough, asthma and diabetes. Seven per cent of the men reported exposure to asbestos, 10% to welding fumes, and 6% to silica. Among those who reported work related dust exposure there was a higher proportion of smokers, and smokers exposed to dust smoked more tobacco per day than non exposed smokers. In the group of men 30-59 years of age, who did not indicate exposure to occupational pollutants 2.7% reported previous pleural effusions. However, among asbestos exposed men of the same ages, the prevalence was more than doubled (5.7%, p less than 0.01). This finding was highly significant in a logistic regression model where age and smoking habits were included. The data indicate that 10% or more of diagnosed cases of pleurisy could be associated with previous asbestos exposure.