Diesel Exhaust and Coal Mine Dust

Abstract

Conflicting evidence on the carcinogenicity of diesel exhaust (DE) and coal mine dust in occupational settings exist. Exposure measurement in most studies is inferred on the basis of job classifications and may lead to misclassification. Confounding behavioral factors (i.e., smoking) and occupational risk factors (exposure to asbestos, arsenic, radon) need to be considered. We evaluated the epidemiological evidence and current findings of the carcinogenicity of DE and coal mine dust in occupational settings. Pertaining literature was identified through Medline search and recent review articles. Strengths and limitations of recent approaches are discussed. Many epidemiological studies have addressed the question of carcinogenicity in workers exposed to DE, and most showed a low-to-medium increase in the risk of bronchial carcinoma. The pooled relative risk (RR) estimates lie between 1.33 and 1.47, and a consistent rise in risk across various job categories and study designs point to a causal relationship. Data on the carcinogenicity of coal mine dust are less consistent and the potential for confounding by unmeasured risk factors (arsenic, radon, DE) are higher. While silica as one of its components has been evaluated as carcinogenic, there is inadequate evidence for the carcinogenicity of pure coal dust according to the International Agency for Research on Cancer (IARC). There is sufficient evidence for a causal relationship between DE and lung cancer in occupational settings. The evidence for coal mine dust is less convincing, but individual studies show an increase in risk of lung cancer in exposed workers.

Lung cancer mortality is elevated in coal-mining areas of Appalachia

“…We examined whether the distinction between Appalachian and non-Appalachian mining might be related to population density. We found that population density was significantly higher in Appalachian coal-mining areas (95.5 people per square mile) than in other coalmining areas (43.0 people per square mile; Satterthwaite Some research suggests that coal miners may be at elevated risk for lung cancer, although the evidence is equivocal [48]. To address the possibility that our results are due to current or former miners who live in coal-mining areas, we conducted an additional regression model limited to the heavy Appalachian coal-mining counties (N = 66).…”

The influence of diesel exhaust on polycyclic aromatic hydrocarbon-induced DNA damage, gene expression, and tumor initiation in Sencar mice in vivo

“…Hence, the carcinogenic activity of diesel exhaust demonstrated in rats [52] and also presumed for humans based on weak but evident epidemiological findings [53] is mechanistically explainable at the molecular level. However, the effects found in rats were only small and not reproducible at low doses of diesel exhaust (< 2000 µg/m 3 ), or shorter than life-time exposures and in other species such as mice or hamsters [52].…”

Coal mining is associated with lung cancer risk in Xuanwei, China

“…Numerous health effects associated with underground coal mining have been studied, including pneumoconiosis, tuberculosis, chronic obstructive pulmonary disease (COPD), and other nonmalignant diseases of the lung (Merchant et al, 1986; Kuempel et al, 1995; Isidro et al, 2004). Studies evaluating the risk of lung cancer among underground coal miners have reported conflicting results (Ames et al, 1983; Meijers et al, 1988; Morabia et al, 1992; Swanson et al, 1993; IARC Monographs on the Evaluation of the Carcinogenic Risks to Human 1997; Jockel et al, 1998; Skowronek and Zemla, 2003; Hoffmann and Jockel, 2006; Attfield and Kuempel, 2008; Miller and MacCalman, 2010).…”