Grant: Travel Awards - Institute Community Support

Purpose: Colorectal cancer screening is less likely among recent immigrants compared to non-immigrants in Canada. Less is known about the modifiable factors that explain this disparity. The objective of this study was to assess how much inequities in income and health care access between recent immigrants and non-immigrants explain (mediate) the disparities in colorectal cancer screening between these two populations. Method: The Vanderweele and Vansteelandt (2010) method of mediation analysis was applied to explain the association between recent immigration and colorectal cancer screening. Pooling eight waves (2003-2012) of the Canadian Community Health Survey, the sample consisted of 130,469 respondents aged 50-75 (n=3784 recent immigrants, i.e. <10 years previous to survey; n=126,685 non-immigrants). Longer-term immigrants were excluded from the analyses. The outcome, screening non-adherence, was defined as having neither received fecal blood testing in the past 2 years nor endoscopy in the past 5 years. Mediators assessed were income (Canadian dollars) and access to a regular medical doctor (MD) (no/yes). Logistic models, adjusted for sex, age, education, marital status, and mediators yielded decomposed effects. Results: Recent immigrants (84% screening non-adherence) had 1.32 times greater odds of screening non-adherence (95%CI: 1.01, 1.73) in comparison to non-immigrant respondents (80% screening non-adherence). Differences in income and MD access between the two groups mediated the screening disparity by 11% (95%CI: 1.03, 1.20) and 2% respectively (95%CI: 1.001, 1.04). Conclusions: These findings contribute to the knowledge of the social determinants of colorectal screening. Eliminating inequalities in income and MD access between recent immigrants and non-immigrants could reduce disparities in screening by 11% and 2%, respectively. Nevertheless, screening non-adherence is high overall and requires public health attention.