Respiratory symptoms and spirometry in experienced coal miners: effects of both distant and recent coal mine dust exposures.
Am J Ind Med 1997 Sep; 32(3):268-274
The influence of distant and recent coal mine dust exposure on respiratory symptoms and spirometry was examined among experienced coal miners. The subjects, consisting of 1,866 male miners who were tested at least twice in the National Study of Coal Workers' Pneumoconiosis (NSCWP), completed questionnaires concerning respiratory symptoms. Mine dust exposure estimates were based on the findings of previous studies. The mean annual exposure concentration decreased from 3.4mg/m3 before rounds one and two of the NSCWP (R1/R2) to 1.0mg/m3 after R1/R2. Prior to R1/R2, the forced expiratory volume in 1 second (FEV1) decreased with increasing exposure level. After R1/R2, no significant difference in the FEV1 was observed between the low and high exposure groups. The pre R1/R2 exposures did not significantly affect the post R1/R2 FEV1. The prevalence of respiratory symptoms increased with increasing dust exposure both before and after R1/R2. The difference in the prevalence of chronic bronchitis between the post R1/R2 exposure levels was not affected by the level of pre R1/R2 exposure. However, the differences in the prevalence of shortness of breath and wheeze between the high and low post R1/R2 exposure levels decreased with increasing pre R1/R2 exposure. The risk factors for experiencing a certain respiratory symptom included a previous report of the same symptom, age, the cessation of mining work, and current smoking. In addition, the risk of respiratory symptoms increased significantly with increasing levels of both distant and recent exposure. For shortness of breath and wheeze, workers with the least amount of distant exposure were most affected by recent exposure. The authors conclude that the impact of coal mine dust exposure on respiratory symptoms is influenced by previous exposures. The current 2.0mg/m3 coal mine dust standard is insufficient for the prevention of respiratory disease.
Spirometry; Respiratory-system-disorders; Coal-miners; Coal-mining; Coal-dust; Occupational-exposure; Exposure-levels; Dusts; Dust-exposure; Respirable-dust; Questionnaires; Risk-factors; Risk-analysis; Demographic-characteristics; Age-factors; Lung-irritants; Pulmonary-system-disorders; Dose-response; Clinical-symptoms;
Author Keywords: mining; coal mine dust; occupational respiratory disease; respiratory symptoms
Dr. Paul K. Henneberger, Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Room 234, 1095 Willowdale Road, Morgantown, WV 26505
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Respiratory-system-disorders
American Journal of Industrial Medicine