How much might universal health insurance reduce socioeconomic disparities in health? : A comparison of the US and Canada.

A strong association between lower socioeconomic status and worse health has been documented within many countries, but little work has been done to compare the strength of this relationship across countries. We compare the strength of the relationship between income and self-reported health in the US and Canada. We find that being below median income raises the likelihood that a middle-aged person is in poor or fair health by about 15 percentage points in the US, compared with less than 8 percentage points in Canada. We also find that this 7 percentage points stronger relationship between low income and poor health in the US compared with Canada is reduced by about 4 percentage points after age 65, the age at which virtually all US citizens receive basic health insurance through the Medicare programme. Income differences in the probability that an individual lacks a usual source of care are also significantly larger in the US than in Canada before the age of 65, but about the same after age 65. Our results are therefore consistent with the theory that the availability of universal health insurance in the US, or at least some other difference that occurs around the age of 65 in one country but not the other, decreases the difference in the strength of the income-health relationship in the US compared with Canada.