Social–Environmental Burden Is Associated with Increased Colorectal Cancer Mortality in Metropolitan Detroit

Abstract

Neighborhood quality affects both socioeconomic factors and exposure to carcinogenic environmental pollutants, but the impacts of these factors on racial disparities in colorectal cancer mortality are not well described. We used the Centers for Disease Control and Prevention Environmental Justice Index social vulnerability module, environmental burden module (EBM), and the combined social–environmental score (SER) to assess relationships with colorectal cancer mortality by race and age in the Metropolitan Detroit Cancer Surveillance System. Among 13,505 patients with colorectal cancer [9,727 non-Hispanic White (NHW) and 3,778 non-Hispanic Black (NHB)], EBM quartile 4 versus 1 was more strongly associated with mortality among NHB early-onset (EO) cases than NHW EO cases [NHB: HR ¼ 1.98, 95% confidence interval (CI), 1.20–3.26; NHW: HR ¼ 1.40, 95% CI, 0.88–2.25]. SER quartile 4 versus 1 was more strongly associated with colorectal cancer mortality in EO (NHB: HR ¼ 1.76, 95% CI, 0.93–3.31; NHW: HR ¼ 1.53, 95% CI, 0.79–2.96) compared with later-onset cases (NHB: HR ¼ 1.15, 95% CI, 0.87–1.52; NHW: HR ¼ 1.39, 95% CI, 1.17–1.65) regardless of race. These associations in EO cases were strongest in colon tumors versus rectal tumors (EO EBM: colon HR ¼ 2.08, 95% CI, 1.24–3.48 vs. rectum HR ¼ 1.03, 95% CI, 0.64–1.66; EO SER: colon HR ¼ 2.57, 95% CI, 1.38–4.79 vs. rectum HR ¼ 0.84, 95% CI, 0.48–1.45). These results suggest the combination of socioenvironmental burdens contributes to age and racial disparities in colorectal cancer mortality in metropolitan Detroit.