Studies examine potential links between coal and cancer in Eastern Kentucky

March 19, 2013-by James Bruggers in Watchdog Earth

What do toenails have to with human health and the environment?

Like hair, they can contain contaminants that are bodies are shedding.

I once had my hair sampled for mercury and, to my delight, found that my mercury levels were not alarming.

Well, in reporting yesterday’s news about reported health disparities between Floyd County, where there’s been a lot of surface mining, and two other eastern Kentucky counties, where there hasn’t been any, I was made aware of two other completed studies that might be link mining and public health and a third one underway now.

Speculation seems to be that very tiny particles of coal-dust might be getting into people’s lungs, where they can move in the blood stream. Or people might be picking up contaminants from contaminated drinking water. Or perhaps pollutants are in the soil. Or maybe it could be because of radon.

All three studies are out University of Kentucky. Both completed studies were published in medical journals in 2011.

One had to do with…. yes, toenail clippings.

It sounds a little weird, I know. But stick with me. But all of this can be found in authoritative write-ups on the Internet.

Researcher Nancy Johnson and her team collected toenail samples from residents in 23 eastern Kentucky counties, where there was coal mining, and compared them to residents’ toenails in Jefferson County, where there is no coal mining, according to an abstract of their findings.

They found some surprising results, according to the abstract of their findings, published in the Journal of Environmental Pathology, Toxicology and Oncology, found here and summed up below:

Lung cancer rates in Appalachian Kentucky are almost twice national rates; colorectal cancer rates are also elevated. Although smoking prevalence is high, it does not explain all excess risk. The area is characterized by poverty, low educational attainment, and unemployment. Coal production is a major industry. Pyrite contaminants of coal contain established human carcinogens, arsenic (As), chromium (Cr), and nickel (Ni). We compared biological exposure to As, Cr, and Ni for adults living in Appalachian Kentucky with residents of Jefferson, a non-Appalachian, urban county. We further compared lung and colon cancer rates, demographics, and smoking prevalence across the study areas. Toenail clipping analysis measured As, Cr, and Ni for residents of 23 rural Appalachian Kentucky counties and for Jefferson County. Reverse Kaplan-Meier statistical methodology addressed left-censored data. Appalachian residents were exposed to higher concentrations of As, Cr, and Ni than Jefferson County residents. Lung cancer incidence and mortality rates in Appalachia are higher than Jefferson County and elsewhere in the state, as are colorectal mortality rates. Environmental factors may contribute to the increased concentration of trace elements measured in residents of the Appalachian region. Routes of human exposure need to be determined.

There’s now a new study just underway at UK that might  shed some additional light, led by Dr. Susanne M. Arnold, described this way:

Preliminary analysis of trace element content in toenail samples reveals higher levels of arsenic, chromium and nickel in Appalachian Kentucky residents than elsewhere in Kentucky. Trace elements are known to promote carcinogenesis by increased oxidative stress, inflammation, DNA damage, and reduced DNA repair efficiency. These findings justify further investigation of the role that trace elements play in the development of lung cancer in this region.

Hypothesis:

The unexpectedly high rate of lung cancer in Appalachian Kentucky is associated with exposure to environmental carcinogens that increase oxidative stress and DNA damage.

They say their purpose “is to try to understand the effects of trace elements such as arsenic and chromium, as well as radon on the development of lung cancer” and that they will “collect information and environmental and biologic specimens from people who live in Appalachian Kentucky” and either have lung cancer or don’t:

By doing this study, the investigators hope to learn why there are more lung cancers in Kentucky’s fifth Congressional District than anywhere else in the nation.

Results aren’t due until late next year.

Now, the other study I discovered was by researcher Jay Christian and others, who found that coal mining could be contributing to higher lung cancer rates in eastern Kentucky.

From the abstract:

We examined geographic patterns of lung cancer incidence in Kentucky. Recent research has suggested that the coal-mining industry contributes to lung cancer risk in Appalachia. We focused on the southeastern portion of the state, which has some of the highest lung cancer rates in the nation.

They found clusters in southeast Kentucky in counties with higher than expected lung cancer rates, where there also a lot of coal mining, concluding:

Environmental exposures related to the coal-mining industry could contribute to the high incidence of lung cancer in southeastern Kentucky. Lack of evidence for this effect in western Kentucky could be due to regional differences in mining practices and access to public water utilities. Future research should collect biological specimens and environmental samples to test for the presence of trace elements and other lung carcinogens.