Heart risks can vary by ethnicity

Cardiovascular disease remains the leading cause of death here in Canada. We know what many of the risk factors are, from hypertension to abnormal cholesterol and triglycerides, to smoking, diabetes, obesity and family history.

In this week’s CMAJ is an interesting study looking at cardiovascular risk factors and heart disease across four ethnic groups, all living in Ontario. While studies have been done in these countries comparing the global burden of disease, each of these countries has their own access to health care and particular social issues. Studies like this have told us that there are higher rates of diabetes in South Asians compared to Canada’s general population. By studying different ethnic groups within Ontario, that would mean they are in the same macro-environment that offers similar access to health care impacting on all these ethnic groups.

Many risk factors are influenced by where you live. For example, anti-smoking legislation, prices of cigarettes, availability of healthy foods etc.  Knowing that, does ethnic background make a difference in the prevalence of 8 risk factors and the prevalence of heart disease and stroke here in Ontario?

Four ethnic groups who lived in Ontario -- white, black, Chinese and South Asian -- were looked at to assess this question as well as the prevalence by age and sex. Are there subgroups that might be at the highest risk?

Funded by the Heart and Stroke Foundation, it was found that the Chinese population had the lowest overall prevalence of heart disease, at 3.2% and stroke, at 0.6%, compared to South Asians who had the highest prevalence of heart disease at 5.2%  and stroke at 1.7%.

Black individuals had the least desirable cardiovascular risk profile but not the worst prevalence of heart disease (3.4%). White people studied had the highest rates of smoking and obesity while black and South Asian population’s had the highest levels of hypertension and diabetes. Interestingly, white males were most likely to smoke and be obese. The prevalence of smoking was also much higher in white females than any other female counterpart.

South Asian and black populations had the higher prevalence of diabetes and hypertension. People of Chinese origin had significantly lower levels of most cardiovascular risk factors, heart disease and stroke. South Asians had intermediate levels of risk factors and the highest prevalence of heart disease and stroke. While Black populations had high levels of cardiovascular risk factors, they did not have the highest rate of cardiovascular disease.

We know that the so-called burden of cardiovascular disease differs across nations. These nations differ by the environment, the health care systems and access to their systems.

Already, a difference is noted in smoking rates compared to the native country. For example, Chinese residents have an 8.7% rate of smoking compared to residents of China at 28.9% . South Asian residents in Ontario smoke at a rate of about 8.6% whereas in India the smoking rate is 15.6%.

Here in Ontario, we have a level playing field with respect to access to health care, yet the risk profiles still did vary by ethnic profiles. This is important. As ethnic populations represent a larger proportion of the Canadian population, it becomes important to target specific risk factors.