Respiratory disease mortality among US coal miners; results after 37 years of follow-up

Abstract

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.

Lung cancer among coal miners, ore miners and quarrymen: smoking-adjusted risk estimates from the synergy pooled analysis of case–control studies

“…By contrast, a hospital-based case-control study found no excess lung cancer risk among Dutch coal miners (12) in line with a case-control study nested into four industrial cohorts (10). Several large cohort studies did not identify an increased lung cancer risk among coal miners either (15)(16)(17)(18). However, a prospective study in Japanese coal miners revealed an elevated smoking-adjusted risk of 2.4 for long-term mining (≥15 years) (14).…”

“…On average subjects in our population-based study worked only seven years as miners or quarrymen, which is a considerably shorter period compared to industrybased cohorts such as those in the US underground coal miner cohort with a mean tenure of 21 years (17,18). Furthermore, about 75% of all cases had ≥20 years since last exposure and none of them worked as a miner or quarryman at the time of diagnosis.…”

“…However, a prospective study in Japanese coal miners revealed an elevated smoking-adjusted risk of 2.4 for long-term mining (≥15 years) (14). Evidence of an association between exposure to quartz and lung cancer, but not with coal mine dust, was found in a large cohort of British coal miners (8), while an extended follow-up of a cohort of US coal miners reported an association with coal mine dust, but not with silica exposure (18), with the British cohort having a longer follow-up and a more robust exposure assessment (30).…”

“…Since then, epidemiological studies have reported mixed results on lung cancer among coal miners (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18), with extended follow-ups of cohort studies among British and US coal miners recently suggesting a positive association. However, exposure-specific results for coal dust and silica were not coherent between the two studies.…”

Physicians’ knowledge on the work-related chronic obstructive pulmonary disease

“…wśród pracowników budowlanych zatrudnionych przy budowie tuneli [15] oraz wśród pracowników przemysłu włókienniczego i tekstylnego, zatrudnionych w narażeniu na pył bawełny i jedwabiu [16]. Analiza piśmiennictwa dowodzi, że także górnicy są szczególnie predysponowani do rozwoju POChP [17][18][19][20], a częstość POChP w tej grupie zawodowej szacuje się na 6-20% wśród osób niepalących i nawet 60% wśród pracowników palących tytoń [20].…”