Examining the association between socioeconomic status and invasive colorectal cancer incidence and mortality in California
A partir des données du registre californien des cancers, cette étude évalue l'association entre le groupe ethnique et le statut socioéconomique des patients, le risque de cancer colorectal invasif ainsi que la mortalité
Background: Colorectal cancer (CRC) incidence and mortality rates vary across race/ethnicity. Socioeconomic status (SES) also influences CRC rates; however, these associations might be inconsistent across racial/ethnic groups and tumor sub-site. We examined associations between area-level SES and CRC incidence and mortality in a population-based registry study of non-Hispanic Whites, African-Americans, Hispanics, and Asians/Pacific Islanders from California. Methods: Data on 52,608 incident CRC cases (1998-2002) and 14,515 CRC deaths (1999-2001) aged ≥50 years were obtained from the California Cancer Registry. Based on 2000 U.S. Census data, each cancer case and death was assigned a multidimensional census tract-level SES index. SES-specific quintiles of CRC incidence and mortality rates, incidence and mortality rate ratios (IRR and MRR), and 95% confidence intervals (CI) were estimated. Analyses were stratified by anatomical site, including left- versus right-sided tumors, race/ethnicity, and stage of disease. Results: Overall CRC incidence and SES did not demonstrate a clear association, yet patterns of associations varied across tumor sub-site and race/ethnicity. Positive associations between SES and CRC incidence were found in Hispanics [SES Q5 v. Q1: IRR=1.54, CI=1.39-1.69], irrespective of the sub-site. For Whites [SES Q5 v. Q1: IRR=0.80, CI=0.77-0.83] and African-Americans [SES Q5 v. Q1: IRR=0.83, CI=0.70-0.97] inverse associations were observed, predominantly for left-sided tumors. Mortality rates declined with increasing SES in Whites, while in Hispanics mortality rates significantly increased with SES. Conclusions: Our findings demonstrate that SES differences in CRC incidence and mortality vary considerably across anatomical sub-site and race/ethnicity. Impact: Studies combining area-level and individual-level SES information are warranted.