Grant: Travel Awards - Institute Community Support

Background: Colorectal cancer is the third most common cause of death in Canada, yet the participation rate in preventive colorectal cancer screening remains low in the country (30%). Though many studies have explored individual-level determinants of screening, area-level determinants of screening remain to be studied in Canada. Objective: This study aimed to assess the association between area-level income and both lifetime- and non-recent colorectal screening in Canadian urban settings. Methods: Two waves of the nationally-representative Canadian Community Health Survey (CCHS) were pooled (2005, 2007), and restricted to urban-dwellers aged 50-75 who were at average risk for colorectal cancer (18,381 respondents). The outcomes assessed were lifetime non-screening (LNS), and non-recent screening (NRS), defined as neither having received a stool-based test in the previous 2 years, nor any form of endoscopy in the previous 5 years. 2006 Canadian Census Dissemination Area income linked to each participant was split into quartile groupings-where Quartile 1 represented the lowest income areas, and Quartile 4 represented the highest income areas. The prevalence of LNS and NRS in Quartiles 1-3 areas were compared to those in Quartile 4 areas. Results: Average LNS and NRS were, respectively, 53% and 65%. Compared to Quartile 4 area residents, those living in Quartile 1, 2, and 3 areas were, respectively, 1.27, 1.25, and 1.15 times more likely to never have been screened in their lifetimes (95 % Confidence Intervals (CI): 1.18-1.26; 1.16-1.34; 1.08-1.24), and 1.18, 1.17, and 1.10 times more likely to not have been screened recently (95% CI: 1.11-1.24; 1.11-1.14; 1.04-1.16). Conclusions: Area-level income appears to be an important predictor of lifetime and non-recent screening. The gradient observed can inform targets for interventions that address the social determinants of screening, while focusing on the overall low level of screening participation.