Abstract 2526: Coal mining and cancer risk: important gaps in public health knowledge.

Coal fueled 42% of electricity generation in the US in 2011 with >1 billion tons mined across 27 states. Considering that 33% of petroleum used in the US comes from Arab States and Venezuela, coal will remain a critical component of US energy policy with national production expected to increase 7.6% by 2035. Given the large spatial extent of coal bearing formations, substantial proportions of the population are now, with more likely to be, exposed to coal mining (CM) activities, e.g. dust from mining and processing, leachates from mine tailings, and smoke from coal combustion. While CM activities are known to release carcinogens such as crystalline silica dust, polyaromatic hydrocarbons, and trace elements (e.g. Cd, As), a systematic review of literature published since 1980 regarding resultant impacts upon cancer rates in potentially exposed populations is equivocal. Occupational studies are designed to provide data concerning the effects of acute or long term exposure. Of 11 such studies identified, 7 found an increased risk of cancer in coal miners (digestive/gastric, lung, all cancers) but 4 found no increased risk (gastric, lung, all cancers). Another 17 studies compared miners to other populations, or examined CM as a risk factor. Nine found associations between CM and increased cancer risk (bladder, gastric, larynx, lung, nasal, all cancers), but 8 found no increased risk (gastric, lung). Finally, 6 studies were identified which examined associations between CM and cancer in the general population. Three found associations between community cancer rates and CM, with those living near CM at increased risk (male colorectal, lung), 2 used spatial statistics to identify cancer clusters associated with CM (breast, lung, respiratory, all cancers), and 1 used community surveys to identify increased self-reported cancer in mining areas. While the strength of these latter studies is limited by weaknesses inherent in ecological and cross-sectional designs, evidence exists to support the biological plausibility that populations near CM activities are at increased risk. Environmental studies have shown that lignite bed leachates are associated with renal pelvic cancer and induce kidney cell culture proliferation; rodents captured from CM areas had greater DNA damage than non-exposed controls; and crystalline silica may be found in coal at high levels and released by burning. In sum, the data are too weak to conclude there is an increased risk of cancer to the general population, to identify which specific populations suffer that risk, or indicate which mitigation strategies may be effectively implemented. While prospective cohort studies might provide such data, the long lag time between exposure and cancer may preclude practicality and other measures of exposure (e.g. toenail clippings, wind patterns) and potential pre-cancerous cellular conditions (e.g. DNA methylation, histone modifications) should be investigated as interim outcomes. Citation Format: Wiley D. Jenkins, Georgia Mueller, W. Jay Christian. Coal mining and cancer risk: important gaps in public health knowledge. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2526. doi:10.1158/1538-7445.AM2013-2526