The University of Kentucky’s Dr. Susanne Arnold and colleagues have been awarded a $1.4 million grant by the U.S. Department of Defense to study potential environmental reasons for the high lung cancer rates in eastern Kentucky. The study, which will last for three years, is now underway.
Kentucky has the highest lung cancer rates in the nation, but counties in the southeastern portion of the state – those in the Fifth Congressional District – have an exceptionally high incidence of lung cancer. Data from the Kentucky Cancer Registry revealed that the age-adjusted incidence rate for lung cancer in Appalachian Kentucky from 2003-2007 was 115.2 cases per 100,000 residents, compared to 61.6 cases per 100,000 residents nationally.
A “ high” lung cancer rate is defined as more than 101.6 cases per 100,000 residents. By this definition, 83 percent of the counties in the Fifth District have high rates, compared to 38 percent for the rest of Kentucky.
Tobacco use is the leading cause of lung cancer, and 25 percent of Kentuckians smoke, compared to the 21 percent of people nationally. But smoking on its own doesn’t explain the discrepancy between southeastern Kentucky and the rest of the nation, Arnold said.
“We know that tobacco is the number one cause of lung cancer, but that isn’t the only factor causing the high cancer burden for southeastern Kentucky,” she said. “So we started to look for other possible reasons. Could environmental carcinogens play a role? That’s what this grant will allow us to investigate.”
Arnold says the idea for the lung cancer study came about because of preliminary data from a study of colon cancer patients in Appalachia. The study examined toenail clippings from patients to assess their exposure to trace elements. Appalachian colon cancer patients showed significantly higher amounts of arsenic, chromium and nickel than non-Appalachian patients, suggesting they had been exposed to these trace elements more extensively.
Although trace amounts of metals (such as iron) are necessary for the body’s normal functions, prolonged exposure to trace elements including arsenic, beryllium, cadmium, cobalt, chromium, nickel and vanadium has been linked to several types of cancer, including lung cancer. These trace elements are known to promote carcinogenesis by increasing oxidative stress, inflammation and DNA damage, and reduced DNA repair efficiency.
There are several potential sources for trace element exposure in southeastern Kentucky. Residents could be exposed through their water source, their soil, the local food sources they eat, or in other unknown ways.
Arnold says her study will define age- and gendermatched cancerous and non-cancerous residents. Each participant will be asked to fill out a questionnaire about his or her smoking habits. Researchers will determine the amount of exposure to trace elements by taking samples of residents’ toenails, hair, urine and blood. To determine the source of the exposure, they’ll also collect samples of water and soil from the home. The biological and environmental samples generated from this study will also be made available to other researchers to use for other studies on health in Appalachia.
This project is also partnering with Kentucky Homeplace, an advocacy organization southeastern Kentucky that was created with the help of late State Rep. Paul Mason of Whitesburg.
“As an eighth-generation Kentuckian, this work is really personal for me,” Arnold said. “ …I feel like it’s our job to be a champion for the people of Appalachia. I hope this study will help us to understand the epidemic that is ravaging southeastern Kentucky and begin to find solutions to this devastating problem.”
Allison Perry is a writer in the public relations department at the University of Kentucky.