P-134 Social determinants of health are risk factors for early onset colorectal cancer in Appalachia

Abstract

The Appalachian mountain range encompasses 420 counties and parallels the eastern seaboard of the United States (US). This region is characterized as being predominantly rural with poverty rates that exceed the national average. Recently, areas in southern and central Appalachia were identified as geographical hot-spots for EOCRC mortality in men. The purpose of this investigation is to describe the relationship between social determinants of health, including educational attainment, poverty, income, unemployment, and access to cancer screening, and the incidence of EOCRC in Appalachia. This is a retrospective cohort analysis of the National Cancer Institutes’ Surveillance, Epidemiology, and End Results (SEER) program. 4,724 patients age 20-49 who were diagnosed with colorectal cancer in Appalachia from 2000-2016 met inclusion criteria and were analyzed. 105 of the 420 Appalachian counties designated by the Appalachian Regional Commission were represented in this study. County-level incidence of EOCRC was calculated (n=105) and the counties in the top (n=25) and bottom (n=27) quartiles for incidence of EOCRC were separated into two cohorts for comparison. County characteristics reported by the American Community Survey from 2012-2016 Census and the National Health Interview Survey (2008-2011) were compared between the cohorts. Appalachian counties above the top quartile for EOCRC incidence were found to have significantly lower levels of educational attainment with significant differences seen at all cutoffs (< 9th grade, < high school, < bachelor’s degree). Appalachian counties above the 75th percentile for EOCRC also have a significantly higher unemployment rates and greater levels of poverty defined as percentage of the population living under 200% of the federal poverty level. Moreover, county-level median household income was found to be inversely related to county incidence of EOCRC. Appalachian counties above the 75th percentile incidence of EOCRC have significantly higher percentage of residents who identify as current smokers or ever smokers. Furthermore, EOCRC incidence in Appalachia inversely correlated with utilization of health screens. Specifically, the top quartile for EOCRC incidence had significantly lower rates of endoscopy use and CRC testing for screening-aged adults. While it is known that social determinants of health play a key role in colorectal cancer morbidity, mortality, and survival, this study shows that social determinants of health are also risk factors for the incidence of EOCRC. We hypothesize that counties with poor social determinants of health (high poverty rates, low educational obtainment, and decreased access to preventative healthcare) may also have higher rates of independent risk factors for EOCRC such as obesity and processed meat consumption. Interestingly, this study demonstrates that EOCRC incidence inversely corelated with county utilization of CRC testing for screening age adults. These results provide data to strongly support public health initiatives in Appalachia aimed at improving these social determinants of health at a county-level. We further hypothesize that tobacco use, processed meat consumption, obesity, and limited access to primary care are some of the likely many factors driving the increased incidence of EOCRC in Appalachia and therefore provide targets for future interventions at the regional level.