The slide depicts the lack of a significant income gradient in Toronto and a significant one in Detroit (low/high income survival rate ratio of 0.80).

And, as hypothesized, a significant country by income interaction was observed (the effect of country was moderated by income level). A Canadian advantaged was observed in the lowest third of income areas (survival rate ratio = 1.30), but not in the other middle to high income areas.

And given the relative commonness of breast cancer such SRRs (reflecting a 20-30% risk ratio) may be thought of as very large in a population attributable risk sense.