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Cardiovascular health

Reasons for heart disease among ethnicities more than skin deep, study says Add to ...

Much is said and written about Canada's multicultural face. But probe a little deeper and you will find that the country's hearts are just as diverse.

New research shows that the prevalence of heart disease and stroke varies markedly among major ethnic groups.

Cardiovascular disease is lowest in the Chinese community, followed by blacks. Rates of heart disease and stroke are highest among those of South Asian descent and Caucasians.

The differences don't appear to be genetic but, rather, reflective of socio-economic status and prevalent lifestyle choices, which appear to be as divergent as the ethnic communities themselves.

"Only a small portion of the risk is genetic," said Maria Chiu, a PhD student at the University of Toronto and co-author of the research. "The risk comes from directly or indirectly modifiable risk factors."

Ms. Chiu, who is also a fellow at the Institute for Clinical Evaluative Sciences, said that there is a reluctance to study ethnicity in Canada, "but it's important that we recognize that there are differences and, as a result, different health-care needs."

The study, published in Tuesday's edition of the Canadian Medical Association Journal, is based on data collected in Ontario by Statistics Canada between 1996 and 2007.

Researchers compared eight recognized risk factors for cardiovascular disease - smoking, obesity, Type 2 diabetes, high blood pressure, stress, fruit and vegetable consumption, physical activity levels and alcohol consumption - as well as socio-economic factors such as education and income in Canada's four largest ethnic groups. The research team also examined the actual rates of heart disease and stroke in each ethnic community.

The research team found some striking differences. For example:

- Only 8.6 per of South Asians smoke, compared with 24.8 per cent of Caucasians.

- The obesity rate in the black community is 14.1 per cent, compared with 4.3 per cent among Chinese Canadians.

- The rate of diabetes among South Asians, 8.1 per cent, is almost double that of Caucasians at 4.2 per cent.

- Hypertension rates were high across the board - one-in-seven Ontarians - but highest in the black and South Asian communities.

- Physical activity rates were lowest among South Asians and Chinese Canadians, with almost 73 per cent getting less than 15 minutes of activity daily.

- Poverty rates were, far and away, highest in the black community, where average annual household income is less than $55,000, compared with almost $79,000 among Caucasians.

- Education rates are highest in the Chinese community, with almost 80 per cent holding a college or university degree, compared with 73 per cent of Caucasians.

- Marriage rates are highest among South Asians, at 63.3 per cent, compared with 40.2 per cent in the Black community.

Ms. Chiu and her research team said that, over all, members of the Chinese community have the best "cardiovascular risk factor profile" with only 4.3 per cent reporting two or more major cardiovascular risk factors (such as smoking, obesity, diabetes, hypertension).

Among South Asians the rate is 7.9 per cent, while among Caucasians it is 10.1 per cent and 11.1 per cent in the black community.

The researchers, however, pointed to a "black paradox" in which black Canadians have some of the worst risk factor profile, but fare relatively well when it comes to actual rates of heart disease and stroke.

Ms. Chiu said that identifying differences is the first step, then the responses can be tailored. She added too that much follow-up research remains, including digging down and distinguishing between immigrants and long-time residents, and examining a broader range of ethnic communities.

Marco Di Buono, director of research at the Heart and Stroke Foundation of Ontario, praised the effort, saying: "This information is really valuable. It shows us where we should focus our efforts and resources."

He said he was surprised, for example, by the poor risk profile in the black community and by the low smoking rates in the Chinese community.

"In heart health - and health care more generally - there isn't a one-size-fits-all message," Dr. Di Buono said. "We need culturally appropriate responses."

Indar Persaud, a 60-year-old medical equipment technician, said that he is acutely aware of the higher risk of cardiovascular disease in the South Asian community because both his mother and father-in-law developed severe heart disease in their 50s.

So when he learned during a recent check-up that he had high blood pressure, Mr. Persaud took action, beginning an exercise regimen and cutting junk food out of his diet. (The tailored program, the Healthy Weight Action Plan, is available free-of-charge on the Heart and Stroke Foundation website.)

At 5-foot-1 and 150 pounds, the Toronto man has, after 10 weeks, dropped five pounds and trimmed three inches from his waist, but, more importantly, his blood pressure has dropped significantly.

Mr. Persaud said his downfall has been "a bit too much Pizza Hut and ice cream," so he is returning to a more traditional South Asian diet that features a lot of fruits and vegetables.

"I know my risk is higher because of my background so I've adjusted," he said.

Jack Tu, a senior scientist at ICES and co-author of the study, noted that almost 60 per cent of the world's population is Chinese or South Asian, but the vast majority of knowledge of cardiovascular risk has been derived mainly from studies conducted in Caucasian populations.

There are nearly two million people of South Asian, Chinese or black descent and more than nine million people of European descent living in Ontario, and the research underscores that they each ethnic group has particular challenges.

"The findings have very important implications for the future of cardiovascular care in Canada, as the proportion of Canada's population in visible minority groups increases over time," Dr. Tu said.

 

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