Geographic determinants of colorectal cancer in Louisiana

Currently, rural residents in the United States (US) experience a greater cancer burden for tobacco-related cancers and cancers that can be prevented by screening. We aim to characterize geographic determinants of colorectal cancer (CRC) incidence in Louisiana due to rural residence and other known geographic risk factors, area socioeconomic status (SES), and cultural region (Acadian or French-speaking).

Primary colorectal cancer diagnosed among adults 30 years and older in 2008-2017 were obtained from the Louisiana Tumor Registry. Population and social and economic data were obtained from US Census American Community Survey. Rural areas were defined using US Department of Agriculture 2010 rural-urban commuting area codes. Estimates of relative risk (RR) were obtained from multilevel binomial regression models of incidence.

The study population was 16.1% rural, 18.4% low SES, and 17.9% Acadian. Risk of CRC was greater among rural white residents (RR Women: 1.09(1.02-1.16), RR Men: 1.11(1.04-1.18)). Low SES was associated with increased CRC for all demographic groups, with excess risk ranging from 8% in Black men (RR: 1.08(1.01-1.16)) to 16% in white men (RR: 1.16(1.08-1.24)). Increased risk in the Acadian region was greatest for Black men (RR: 1.21(1.10-1.33)) and women (RR: 1.21(1.09-1.33)). Rural-urban disparities in CRC were no longer significant after controlling for SES and Acadian region.

SES remains a significant determinant of CRC disparities in Louisiana and may contribute to observed rural-urban disparities in the state. While the intersectionality of CRC risk factors is complex, we have confirmed a robust regional disparity for the Acadian region of Louisiana.