Respiratory disease mortality among US coal miners; results after 37 years of follow-up.
Graber-JM; Stayner-LT; Cohen-RA; Conroy-LM; Attfield-MD
Occup Environ Med 2014 Jan; 71(1):30-39
Objectives: To evaluate respiratory related mortality among underground coal miners after 37 years of follow-up. Methods: Underlying cause of death for 9033 underground coal miners from 31 US mines enrolled between 1969 and 1971 was evaluated with life table analysis. Cox proportional hazards models were fitted to evaluate the exposure-response relationships between cumulative exposure to coal mine dust and respirable silica and mortality from pneumoconiosis, chronic obstructive pulmonary disease (COPD) and lung cancer. Results: Excess mortality was observed for pneumoconiosis (SMR=79.70, 95% CI 72.1 to 87.67), COPD (SMR=1.11, 95% CI 0.99 to 1.24) and lung cancer (SMR=1.08; 95% CI 1.00 to 1.18). Coal mine dust exposure increased risk for mortality from pneumoconiosis and COPD. Mortality from COPD was significantly elevated among ever smokers and former smokers (HR=1.84, 95% CI 1.05 to 3.22; HRK=1.52, 95% CI 0.98 to 2.34, respectively) but not current smokers (HR=0.99, 95% CI 0.76 to 1.28). Respirable silica was positively associated with mortality from pneumoconiosis (HR=1.33, 95% CI 0.94 to 1.33) and COPD (HR=1.04, 95% CI 0.96 to 1.52) in models controlling for coal mine dust. We saw a significant relationship between coal mine dust exposure and lung cancer mortality (HR=1.70; 95% CI 1.02 to 2.83) but not with respirable silica (HR=1.05; 95% CI 0.90 to 1.23). In the most recent follow-up period (2000-2007) both exposures were positively associated with lung cancer mortality, coal mine dust significantly so. Conclusions: Our findings support previous studies showing that exposure to coal mine dust and respirable silica leads to increased mortality from malignant and non-malignant respiratory diseases even in the absence of smoking. Errata.
Coal-mining; Coal-miners; Morbidity-rates; Mortality-rates; Respiratory-system-disorders; Pulmonary-system; Pulmonary-system-disorders; Pulmonary-function; Pulmonary-disorders; Diseases; Coal-dust; Hazards; Exposure-levels; Dust-exposure; Dusts; Dust-particles; Particulates; Statistical-analysis; Pneumoconiosis; Epidemiology; Cancer; Surveillance
Judith M Graber, Division of Environmental Epidemiology and Statistics, Environmental Occupational Health Sciences Institute, Rutgers University, 170 Frelinghuysen Road, 234D, Piscataway, NJ 08854
Agriculture, Forestry and Fishing
Occupational and Environmental Medicine
University of Illinois at Chicago