Abstract A106: Neighborhood socioeconomic deprivation is associated with higher risk of diagnosis with nonlocalized colorectal cancers

Abstract

Abstract Background: Previous studies have found that, in the US, the incidence rate for colorectal cancer (CRC) is disproportionally high among persons residing in socioeconomic deprived neighborhoods. However, no previous studies have determined if there are disparities in incidence or tumor stage at diagnosis for CRC according to socioeconomic conditions in the neighborhood of residence after adjusting for individual-level CRC risk factors. Methods: Data were obtained from the ongoing NIH-AARP Diet and Health Study, a prospective cohort of 566,402 persons residing in 6 US states and 2 metropolitan areas who were 50-71 years of age at baseline (1995-1996). Detailed individual-level data were obtained on diet, lifestyle and other cancer risk factors using questionnaires. For this analysis, we excluded participants who reported a history of CRC at the time of the baseline questionnaire. CRC incidence was then ascertained from tumor registries through December 31,2003. We used an empirically derived neighborhood socioeconomic deprivation index from linked 2000 US census data based on participants’ home addresses at the time of the baseline questionnaire. The index was categorized into quintiles at the census-tract level. We used proportional hazards models that accounted for clustering of persons within census tracts to separately estimate the hazard ratios for CRC incidence and tumor stage at the time of diagnosis (based on SEER summary staging system). We defined regional, distant or unstaged tumors as non-localized. Results: There were 6,934 incident cases of CRC among the 560,288 eligible participants included in the analyses, of which 59% were non-localized. The age and sex adjusted incidence of CRC among the cohort was 17.5 per 10,000 person-years. The incidence rate was 16.2% among persons residing in census-tracts in the first (least deprived) socioeconomic quintile and 19.8% for the 5th (most deprived) quintile. In proportional hazard models that adjusted for individual-level education and demographic, diet and lifestyle factors, those in the most deprived census-tracts had a higher incidence of CRC, overall (adjusted hazard ratios (HR)=1.16:95% confidence intervals (CI) 1.04-1.29); and non-localized CRC, compared to persons residing in the least socioeconomically deprived (first quintile) census-tracts. Conclusion: Persons residing in socioeconomically deprived neighborhoods were more likely to be diagnosis with non-localized CRC. This may contribute to neighborhood socioeconomic disparities in mortality for CRC. Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A106.