Increasing rates of ischemic heart disease in the Native population of Ontario, Canada

Background: The prevalence of ischemic heart disease (IHD) has been declining in North America since the 1960s. Over this time, Native populations, which have traditionally had low rates of IHD, have undergone striking lifestyle changes that may have had health consequences. In this context, IHD trends in the Native communities of Ontario, Canada, were evaluated. Objective: To assess trends in admission rates for IHD in the Native population of Ontario compared with the general population of Ontario. Methods: A comprehensive administrative database of all hospital admissions in Ontario 1981 to 1997, was used. Age- and sex-adjusted rates of hospital admissions with ii-ID-related diagnostic or procedure codes were determined in all residents of Ontario communities that had regular census participation and at least 95% of their population claiming Native origins (N=16874 in 1991). Comparison was made with all residents of the surrounding northern Ontario region (N=822 450) and of the whole province (N=10 084 885). Results: In 1981, the rate of IHD admissions was similar in all groups, at 99 to 124 per 10 000 persons. By 1997, it decreased to 82 per 10 000 in the province (slope, -1.09; 95% confidence interval, -1.26 to -0.91), with a similar trend in northern Ontario. However, in the Native communities, it increased to 155 per 10 000 (slope, 5.6; 95% confidence interval, 3.8-7.5). A similar trend was seen for acute myocardial infarction admissions, a more precisely coded subset of IHD. Spurious causes of increasing rates were ruled out. Conclusions: Hospitalizations for IHD have doubled in the Native population despite declining rates in the general population. These findings document an alarming trend in Native health and support the need for further research and targeted intervention.