Associations of Census-Tract Poverty with Subsite-Specific Colorectal Cancer Incidence Rates and Stage of Disease at Diagnosis in the United States

Background. It remains unclear whether neighborhood poverty contributes to differences in subsitespecific colorectal cancer (CRC) incidence. We examined associations between censustract poverty and CRC incidence and stage by anatomic subsite and race/ethnicity. Methods. CRC cases diagnosed between 2005 and 2009 from 15 states and Los Angeles County (N = 278, 097) were assigned to 1 of 4 groups based on censustract poverty. Ageadjusted and stagespecific CRC incidence rates (IRs) and incidence rate ratios (IRRs) were calculated. Analyses were stratified by subsite (proximal, distal, and rectum), sex, race/ethnicity, and poverty. Results. Compared to the lowest poverty areas, CRC IRs were significantly higher in the most impoverished areas for men (IRR = 1.14 95% CI 1.121.17) and women (IRR = 1.06 95% CI 1.051.08). Rate differences between high and low poverty were strongest for distal colon (male IRR = 1.24 95% CI 1.201.28; female IRR = 1.14 95% CI 1.101.18) and weakest for proximal colon. These rate differences were significant for nonHispanic whites and blacks and for Asian/Pacific Islander men. Inverse associations between poverty and IRs of all CRC and proximal colon were found for Hispanics. Latetoearly stage CRC IRRs increased monotonically with increasing poverty for all race/ethnicity groups. Conclusion. There are differences in subsitespecific CRC incidence by poverty, but associations were moderated by race/ethnicity.