|See below for example of how to use interactive version of map|
Here are two possible causes: Appalachian counties are high in arsenic and chromium, and Central Kentucky has high potential for radon gas, which can accumulate under buildings. "The National Cancer Institute says radon by itself is the second-leading cause of lung cancer in the United States, and most radon-related deaths occur among smokers," Ungar notes. "Kentucky has no laws requiring radon testing for single- or multi-family homes, schools or businesses; and no laws mandating radon-resistant construction of new homes," according to Ellen Hahn, a UK professor of nursing and public health.
"While doctors aren’t sure how smoking interacts with such carcinogens in the body," Ungar writes, "some theorize that when smoking damages lung cells’ DNA, the lungs become more susceptible to damage from other toxins." (Read more) The map above is interactive on the Kentucky Cancer Registry website. Here's an example of how to display county data, which also shows the beginning of the county list ranked by lung-cancer rate; a map of county lung cancer death rates is also available: