EXPOSURE-RESPONSE ANALYSIS OF MORTALITY AMONG COAL-MINERS IN THE UNITED-STATES

The quantitative relationship between exposure to respirable coal mine dust and mortality from nonmalignant respiratory diseases was investi gated in a study of 8,878 working male coal miners who were medically examined from 1969 to 1971 and followed to 1979. Exposure-related mort ality was evaluated using Cox proportional hazards modeling for underl ying or contributing causes of death and modified lifetable methods fo r underlying causes. For pneumoconiosis mortality, the lifetable analy ses showed increasing standardized mortality ratios (SMRs) with increa sing cumulative exposure category. Significant exposure-response relat ionships for mortality from pneumoconiosis (p < 0.001) and from chroni c bronchitis or emphysema (p < 0.05) were observed in the proportional hazards models after controlling for age and smoking. No exposure-rel ated increases in lung cancer or stomach cancer were observed. Pneumoc oniosis mortality was found to vary significantly by the rank of coal dust to which miners were exposed. Miners exposed at or below the curr ent U.S. coal dust standard of 2 mg/m(3) over a working lifetime, base d on these analyses, have an elevated risk of dying from pneumoconiosi s or from chronic bronchitis or emphysema. (C) 1995 Wiley-Liss, Inc.