RESPIRATORY SYMPTOMS AND SPIROMETRY IN EXPERIENCED COAL-MINERS - EFFECTS OF BOTH DISTANT AND RECENT COAL-MINE DUST EXPOSURES

The goal of this study was to determine whether respiratory symptoms w ere associated with the lower concentrations of respirable coal mine d ust that were required by the U.S. Coal Mine Health and Safety Act (CM HSA) of 1969. The subjects were 1,866 male miners who had participated in the National Study of Coal Workers' Pneumoconiosis (NSCWP) and bee n tested at least twice, initially in either Round I (Ill) (1969-71) o r Round 2 (R2) (1972-75) and then finally in Round 4 (R4) (1985-88). S elf-reported information elicited with a standardized questionnaire tv as used to determine the presence at the final round (i.e., R-4) of ch ronic bronchitis, shortness of breath, and wheeze. Cumulative coal min e dust exposure was characterized for both the pre- and post-CMHSA per iods. Controlling for age and other potential confounders, increased r isks for the symptoms were associated with higher levels of both measu rements of exposure. Moreover the adverse effects of the lower post-CM HSA exposures were evident for shortness of breath and wheeze especial ly among subjects who had little pre-CMHSA coal mining experience. The se findings provide additional evidence of the limitations of the curr ent 2.0 mg/m(3) coal mine dust standard to prevent respiratory disease . (C) 1997 Wiley-Liss, Inc.