Cardiovascular Risk Ethnicity 20150810

People who come to Canada are generally healthier to begin with but with time may eat more fatty foods, more meat and more processed foods, says Maria Chiu, a scientist at the Institute for Clinical Evaluative Sciences. (Canadian Press)

Heart disease and stroke risks showed "striking differences" for South Asian men, black men and women and Chinese men over a 12-year period, a new Canadian study suggests.

Obesity rates rose among all of the ethnic groups, with the largest relative increase among Chinese men, Maria Chiu, a scientist at the Institute for Clinical Evaluative Sciences in Toronto and her team reported in Monday's issue of the journal BMJ Open.

Until now, the overall trends in cardiovascular risk factors in the general population were known, but any differences between ethnic groups hadn't been studied. 

The study was based on data from almost 220,000 Ontario residents who responded to Statistics Canada's Canadian Community Health Surveys from 2001 to 2012.

"What we found was that obesity in relative terms increased the most among Chinese men," Chiu said in an interview.

"Even small increases in weight can increase their risk of diabetes and other major diseases by much more than the white population."

Obesity can lead to Type 2 diabetes, which raises the risk of heart attack, stroke and other serious health conditions such as kidney failure.

Diet is getting progressively worse as fruit and vegetable consumption declined in many of the ethnic groups, she said.

The findings included:

  • Obesity rates among Chinese men more than doubled from about three per cent to nearly six per cent.
  • The prevalence of diabetes doubled among South Asian men (from nearly seven per cent  to 15 per cent) and black women (from six per cent to 12 per cent).
  • In general, black women were most likely to be obese and less likely to consume fruits and vegetables regularly. They were also among those reporting the highest levels of psychosocial stress.
  • The proportion of South Asian men who said they ate fruits and vegetables fewer than three times a day increased from about 21 per cent to nearly 28 per cent.

Smoking rates increased among Chinese men and black women, which suggests smoking cessation strategies could be targeted to them using culturally sensitive awareness messages, Chiu said.

Chiu also studies how conducive neighbourhoods are to walking. Improving how walkable areas are could be a community-wide approach to potentially decrease diabetes rates in all ethnic groups.

Ethnic minority groups also tended to have household incomes that were on average $10,000 to $30,000 less than the white population, despite their education status being about the same.

"We can't ignore the socioeconomic factors that play a role in these differences," Chiu said.

Address prevention next

Dr. Sonia Anand, a researcher in population cardiovascular health at McMaster University in Hamilton, welcomed the findings on how risk factors change over time.

"This work is important really for the next step, which is how to address the issue of prevention," said Anand, who was not involved in the study.

Besides more walkable communities, other strategies to try to influence health behaviours include increasing the availability of healthy foods and strengthening policies that discourage smoking.

Ved Sharma, 75, of Mississauga, Ont., was diagnosed with Type 2 diabetes seven years ago. His complications included foot problems, a clot-related stroke last year and poor kidney function.

"They found that my left eye is totally affected so 80 per cent of my vision is gone," Sharma said.

Sharma said he ate fried foods in middle age and he wasn't fond of exercise. Now he watches his diet closely, takes insulin and tries to be more physically active.

One of the limitations of the study was that the data were self-reported. The study's authors said it is difficult to disentangle the trends they observed from immigration and the tendency for immigrants' cardiovascular health to decline as they reside longer in Western cultures.

Chiu said there's no reason to believe the trends would not be seen in other provinces and territories. 

With files from The Canadian Press and CBC's Vik Adhopia