Disparities in receipt of screening tests for cancer, diabetes and high cholesterol in Ontario, Canada: a population-based study using area-based methods

Objectives — Few have compared socio-economic disparities in screening tests for cancer with recommended tests for other chronic diseases. The authors examined whether receipt of testing for colorectal, cervical and breast cancer, as well as diabetes and high cholesterol, differs by neighbourhood-level socio-economic and recent immigrant status.

Methods — The authors conducted a population-based retrospective cohort study of patients identified as screen-eligible in 2009 living in Ontario, Canada. Postal codes were used to assign residents to a dissemination area (DA). Using Canadian census data, DAs were stratified by income quintile and proportion of recent immigrants. Prevalence of screening for cancer (colorectal, cervical, breast), diabetes, and high cholesterol, using administrative data, and prevalence ratios (least/most advantaged) were calculated.

Results — The cohort comprised 7,652,592 people. Receipt of screening for colorectal cancer (women 61.6%; men 55.1%) and breast cancer (59.9%) were the lowest and diabetes (women 72.9%; men 61.4%) and high cholesterol (women 82.4%; men 70.3%) were the highest. The authors found disparities in the receipt of all tests, with the lowest uptake and largest disparities for cancer screening among those living in both low-income and high-immigration DAs: colorectal – women 48.6%; RR 0.77; 95% CI (0.74-0.79) and men 40.6%; RR 0.71 (0.68-0.74); cervical – 52.0%; RR 0.80 (0.78-0.81) and breast – 45.7%; RR 0.74 (0.72-0.77).

Conclusion — People living in low-income and high-immigration DAs had the lowest screening participation for all tests, although disparities were highest for cancer. An organized integrated chronic disease screening strategy leveraging the higher diabetes and high cholesterol screening participation may increase screening for cancer and other chronic diseases in never- and underscreened populations.