A nested case-control study of inflammatory biomarkers and colorectal cancer risk in the southern community cohort study

Authors: Marlow EC, Warren Anderson S, Cai Q, Steinwandel M, Zheng W, Blot WJ

Category: Cancer Health Disparities
Conference Year: 2020

Abstract Body:
Purpose: Previous cohort studies identified potential racial and sex differences in the associations between inflammatory pathways and colorectal cancer (CRC) risk, where stronger associations were seen between dietary inflammatory indexes and CRC risk among white and male participants than among African American and female participants. Our study’s purpose is to evaluate associations between two inflammation biomarkers, total homocysteine (tHcy) and total cysteine (tCys), with CRC risk in the Southern Community Cohort Study (SCCS), to determine whether race and sex differences are present within the cohort. Methods: The nested case-control study uses data from the prospective SCCS. Participants were recruited from 2002 to 2009 and data were linked to state cancer registries through December 31, 2016. We identified 248 incident CRC cases and matched 456 controls to cases based on age, race, sex, and recruitment source from community health centers or the general population in the southeastern United States. This cohort offers high representation from groups with disproportionally high burden of cancer, including African Americans, low socioeconomic status, and individuals with diabetes or obesity. We estimated odd ratios (OR) and 95% confidence intervals (CI) for CRC risk with inflammation biomarker levels overall and by race and sex strata. Results: We observed modest evidence of associations between inflammation biomarkers and CRC risk. The adjusted OR (95%CI) for comparisons between the tertile (T3) for highest levels of tHcy versus the lowest tertile (T1) was 1.52 (1.00, 2.31), and the adjusted OR (95%CI) for comparisons between T3 vs T1 for tCys was 0.72 (0.47,1.09). Associations were most evident for tHcy among white participants (T3 vs T1 OR=2.66, 95%CI:0.98,7.21), and for tCys among male participants (T3 vs T1 OR=0.44, 95%CI:0.20,0.97). Conclusions: We observed associations between tHcy and tCys with CRC risk in the hypothesized direction of association, where associations were strongest among male and white participants. Future studies are warranted to investigate the role of inflammation in CRC prevention and how the effect may vary by demographic factors.

Keywords: inflammatory cytokines, risk disparities, colorectal cancer