Table 3.

Parameter estimates from segmented regression model assessing the change in trend for the income and immigration inequality ratio for colorectal cancer screening after introduction of a population-based screening program in Ontario in April 2008

A. Effect of program on income inequality ratio
Intercept (95% CI)Trenda before screening program was introduced (95% CI)Step change the year screening program was introduced (95% CI)Trenda after screening program was introduced (95% CI)Net change in trenda after screening program introduced (95% CI)
Recent immigrantsColorectal screening (overall)0.81 (0.77–0.85)−0.01 (−0.01–0.00)0.06 (0.01–0.11)0.01 (000–0.02)0.02 (0.01–0.03)
FOBT0.78 (0.73–0.84)0.01 (0.00–0.02)0.08 (0.01–0.15)0.02 (0.01–0.04)0.02 (0.00–0.03)
Colonoscopy0.96 (0.93–0.99)−0.03 (−0.03 to −0.02)0.04 (0.00–0.08)0.00 (−0.01–0.01)0.03 (0.02–0.04)
Long-term residentColorectal screening (overall)0.92 (0.90–0.93)−0.01 (−0.01 to −0.01)0.04 (0.02–0.06)−0.01 (−0.01–0.00)0.00 (0.00–0.01)
FOBT0.82 (0.79–0.85)0.01 (0.00–0.02)0.05 (0.00–0.09)0.02 (0.01–0.03)0.01 (0.00–0.02)
Colonoscopy1.06 (1.04–1.08)−0.03 (−0.03 to −0.02)0.02 (−0.01–0.04)−0.01 (−0.01–0.00)0.02 (0.01–0.02)
All residents in lowest and highestColorectal screening (overall)0.91 (0.89–0.93)−0.01 (−0.01 to −0.01)0.04 (0.02–0.07)0.00 (−0.01–0.00)0.01 (0.00–0.01)
income quintilesFOBT0.80 (0.77–0.83)0.01 (0.00–0.02)0.04 (0.00–0.08)0.02 (0.01–0.03)0.01 (0.00–0.02)
Colonoscopy1.08 (1.05–1.10)−0.03 (−0.03 to −0.02)0.02 (−0.01–0.05)−0.01 (−0.01–0.00)0.02 (0.01–0.03)
B. Effect of program on immigration inequality ratio
Intercept (95% CI)Trendb before screening program was introduced (95% CI)Step change the year screening program was introduced (95% CI)Trendb after screening program was introduced (95% CI)Net change in trendb after screening program introduced (95% CI)
Lowest income quintileColorectal screening (overall)0.79 (0.75–0.82)00.01 (−0.02–0.00)0.05 (0.00–0.10)0.02 (0.01–0.03)0.03 (0.02–0.05)
FOBT0.88 (0.85–0.92)0.00 (−0.01–0.01)−0.01 (−0.06–0.03)0.06 (0.05–0.07)0.06 (0.05–0.07)
Colonoscopy0.76 (0.72–0.81)−0.03 (−0.04 to −0.01)0.06 (−0.01–0.12)0.01 (0.00–0.02)0.03 (0.02–0.05)
Highest income quintileColorectal screening (overall)0.79 (0.75–0.82)00.01 (−0.02–0.00)0.05 (0.00–0.10)0.02 (0.01–0.03)0.03 (0.02–0.05)
FOBT0.89 (0.84–0.94)0.00 (−0.01 to 0.01)−0.05 (−0.12 to 0.02)0.05 (0.04–0.07)0.05 (0.04–0.07)
Colonoscopy0.84 (0.82–0.87)−0.03 (−0.03 to −0.02)0.03 (0.00–0.06)−0.01 (−0.01–0.00)0.02 (0.01–0.03)
All residents in lowest and highestColorectal screening (overall)0.81 (0.79–0.84)−0.02 (−0.03 to −0.01)0.04 (0.00–0.08)0.01 (0.00–0.02)0.03 (0.02–0.04)
income quintilesFOBT0.80 (0.76–0.84)0.00 (−0.01–0.01)0.00 (−0.06–0.05)0.06 (0.05–0.07)0.06 (0.04–0.07)
Colonoscopy0.89 (0.84–0.93)−0.04 (−0.05 to −0.03)0.04 (−0.02–0.10)0.00 (−0.01–0.01)0.04 (0.02–0.06)
  • NOTE: Income inequality ratio: colorectal cancer screening rate in lowest income quintile divided by colorectal cancer screening rate in highest income quintile. Immigration inequality ratio: colorectal cancer screening rate in recent immigrants divided by colorectal cancer screening rate in long-term residents.

  • aAverage change in inequality ratio per year (e.g., 0.01 denotes a 1% narrowing of the ratio per year; −0.03 denotes a 3% widening in the ratio per year).

  • bAverage change in inequality ratio per year (e.g., 0.01 denotes a 1% narrowing of the ratio per year; −0.03 denotes a 3% widening in the ratio per year).