Correlation between respiratory symptoms and pulmonary function in asbestos-exposed workers.

Studies of respiratory questionnaire efficacy have emphasized reliability of responses; few have validated symptom response with objective measures of pulmonary function. To determine whether respiratory symptoms are associated with diminished pulmonary function, symptoms reported on the American Thoracic Society (ATS-DLD-78A) questionnaire were correlated cross-sectionally with measured spirometric volumes in 816 asbestos-exposed workers. Cough, phlegm, wheeze, and dyspnea were inversely related to pulmonary function. Cough, phlegm, and chronic bronchitis were associated with a 2 to 8% reduction (p < 0.001) in predicted values for forced vital capacity (FVC) and forced expiratory volume (FEV1); wheeze and dyspnea were clinically more significant, with an 11 to 17% reduction (p < 0.001). Wheeze, dyspnea, and roentgenographic fibrosis were all significant independent predictors of risk for restrictive impairment. These results support the validity of the ATS questionnaire as an epidemiologic tool and emphasize the importance of clinical history in assessing respiratory status.