Correlates of preclinical cardiovascular disease in Indigenous and Non-Indigenous Australians: a case control study

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Abstract

Background
In 2001 there were approximately 460,000 indigenous people in Australia, accounting for 2.4% of the population. However persons greater than 40 years old account for proportionately fewer indigenous people, reflecting the fact that indigenous people are much more likely to die before they are old than the general Australian public: men at 56 years; women at 63 years 1-9. In addition, death rates are estimated to be four times higher in indigenous than in non-indigenous Australians.

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In 2002 the leading cause of death in indigenous people was cardiovascular disease (CVD), responsible for 1/3 of all deaths, followed by ischemic heart disease (16%) and stroke (9%)1-8. Of indigenous Australians aged 35├óÔé¼ÔÇ£44 years, 16% reported a cardiovascular condition, with the rate increasing to 31% for those aged 45 to 54 years, and to 47% for those aged 55 years and over. The prevalence of cardiovascular disease is greater in remote areas. Coronary heart disease is 3├óÔé¼ÔÇ£4 times higher for males and females than in non-indigenous people10,11. Indigenous people are much more likely to die of CVD than non-indigenous people at any age, especially in younger age groups ├óÔé¼ÔÇ£ the death rate among 25├óÔé¼ÔÇ£54 year olds was 10 times higher than other Australians.

Atherosclerotic risk factors are more prevalent in the indigenous community; hypertension is the most common risk factor. Diabetes mellitus (DM) is 2├óÔé¼ÔÇ£4 times more prevalent in indigenous than in non-indigenous people, with the onset of DM at a younger age10,11, and a higher reported mortality (7.6% vs. 2.4%) in indigenous patients with DM than in their Caucasian counterparts. Chan et al12 have reported that traditional cardiovascular risk factors are associated with increased atherosclerotic burden (measured by carotid intimamedia thicknessIMT) in indigenous subjects. In this study we sought whether this preclinical cardiovascular disease was related to ethnicity (which is a marker of race and a number of socio-economic factors) independent of differences in risk factors.

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