Avoidable mortality by neighbourhood income in Canada: 25 years after the establishment of universal health insurance.

To examine neighbourhood income differences in deaths amenable to medical care and public health over a 25-year period after the establishment of universal insurance for doctors and hospital services in Canada. Data for census metropolitan areas were obtained from the Canadian Mortality Database and population censuses for the years 1971, 1986, 1991 and 1996. Deaths amenable to medical care, amenable to public health, from ischaemic heart disease and from other causes were considered. Data on deaths were grouped into neighbourhood income quintiles on the basis of the census tract percentage of population below Canada's low-income cut-offs. From 1971 to 1996, differences between the richest and poorest quintiles in age-standardised expected years of life lost amenable to medical care decreased 60% (p<0.001) in men and 78% (p<0.001) in women, those amenable to public health increased 0.7% (p = 0.94) in men and 20% (p = 0.55) in women, those lost from ischaemic heart disease decreased 58% in men and 38% in women, and from other causes decreased 15% in men and 9% in women. Changes in the age-standardised expected years of life lost difference for deaths amenable to medical care were significantly larger than those for deaths amenable to public health or other causes for both men and women (p<0.001). Reductions in rates of deaths amenable to medical care made the largest contribution to narrowing socioeconomic mortality disparities. Continuing disparities in mortality from causes amenable to public health suggest that public health initiatives have a potentially important, but yet un-realized, role in further reducing mortality disparities in Canada.