receiving chemotherapy
Photo by Rhoda Baer
New research suggests that people living in the Appalachian region of the US are more likely to develop cancer than people in the rest of the country.
The study showed that Appalachians had a significantly higher incidence of cancer overall and higher rates of many solid tumor malignancies.
However, lymphoma rates were similar between Appalachians and non-Appalachians, and Appalachians had a significantly lower rate of myeloma.
This research was published in Cancer Epidemiology, Biomarkers & Prevention.
“The Appalachian region, which extends from parts of New York to Mississippi, spans 420 counties in 13 US states, and about 25 million people reside in this area,” said study author Reda Wilson, MPH, of the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
“This region is primarily made up of rural areas, with persistent poverty levels that are at least 20%, which is higher than the national average.”
In 2007, the CDC’s National Program of Cancer Registries (NPCR) published a comprehensive evaluation of cancer incidence rates in Appalachia between 2001 and 2003.
The data showed higher cancer rates in Appalachia than in the rest of the US. However, this publication had some shortcomings, including data that were not available for analysis.
“The current analyses reported here were performed to update the earlier evaluation by expanding the diagnosis years from 2004 to 2011 and including data on 100% of the Appalachian and non-Appalachian populations,” Wilson said.
For this study, Wilson and her colleagues used data from the NPCR and the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program. Together, NPCR and SEER cover 100% of the US population.
The researchers analyzed the Appalachian population by region (north, central, and south Appalachia), gender, race (black and white only), and Appalachian Regional Commission-designated economic status (distressed, at-risk, transitional, competitive, and attainment). And the team compared these data with data on the non-Appalachian population.
The results showed that cancer incidence rates (IRs) were elevated among Appalachians regardless of how they were categorized. The IRs were per 100,000 people, age-adjusted to the 2000 US standard population.
The IR for all cancers was 565.8 for males in Appalachia and 543.0 for non-Appalachian males (P<0.05). And the cancer IRs for females were 428.7 in Appalachia and 418.2 outside the region (P<0.05).
There was no significant difference between the regions in IRs for lymphomas. The Hodgkin lymphoma IRs were 3.1 in Appalachian males, 3.2 in non-Appalachian males, and 2.5 for females in both regions.
The non-Hodgkin lymphoma IRs were 23.3 in Appalachian males, 23.4 in non-Appalachian males, 16.4 in Appalachian females, and 16.3 in non-Appalachian females.
Myeloma IRs were significantly lower in Appalachia (P<0.05). The myeloma IRs were 7.3 in Appalachian males, 7.5 in non-Appalachian males, 4.7 in Appalachian females, and 4.9 in non-Appalachian females.
There was no significant difference in leukemia IRs among males, but females in Appalachia had a significantly higher leukemia IR (P<0.05). The leukemia IRs were 16.9 in Appalachian males, 16.7 in non-Appalachian males, 10.4 in Appalachian females, and 10.2 in non-Appalachian females.
“Appalachia continues to have higher cancer incidence rates than the rest of the country,” Wilson said. “But a promising finding is that we’re seeing the gap narrow in the incidence rates between Appalachia and non-Appalachia since the 2007 analysis, with the exception of cancers of the oral cavity and pharynx, larynx, lung and bronchus, and thyroid.”
“This study helps identify types of cancer in the Appalachian region that could be reduced through more evidence-based screening and detection. Our study also emphasizes the importance of lifestyle changes needed to prevent and reduce cancer burden.”
The researchers noted that this study did not differentiate urban versus rural areas within each county, and data on screening and risk factors were based on self-reported responses.
Furthermore, cancer IRs were calculated for all ages combined and were not evaluated by age groups. Future analyses will be targeted toward capturing these finer details, Wilson said.
