Newer Canadian immigrants have fewer heart health risks

Immigrants who have lived in Canada for more than 15 years are at greater risk of developing cardiovascular disease than those who have lived in the country for a shorter period of time, according to research by the Institute for Clinical Evaluative Sciences.

Immigrants who have lived in Canada for more than 15 years are at greater risk of developing cardiovascular disease than those who have lived in the country for a shorter period of time, according to researchers.

The study by the Institute for Clinical Evaluative Sciences (ICES) was released Tuesday and is published in the Canadian Journal of Cardiology.

Using data from Statistics Canada’s national population and Canadian community healthy surveys from 1996-2007, it focused on immigrants living in Ontario, where the majority of the about 250,000 people who migrate to the country annually usually settle.

"We found a negative acculturation effect, in that long-term residents of Ontario had worse cardiovascular risk profiles than recent immigrants," said Maria Chiu, the study’s principal investigator and an ICES doctoral fellow.

"Moreover, the degree to which cardiovascular health declined was different for different ethnic groups." 

The study notes there is growing evidence that cardiovascular risk profiles differ across Canada’s major ethnic groups. It assessed 163,797 participants:

  • 154,653 white individuals.
  • 3,364 South Asians.
  • 3,038 Chinese.
  • 2,742 black individuals.

Chiu and her fellow researchers, from institutes and hospitals affiliated with the University of Toronto and University of Ottawa, looked at the prevalence of risk factors for heart disease and stroke among immigrants who had resided in Ontario for at least 15 years, compared with those who had lived in the province less than 15 years.

They found that for all ethnic groups, cardiovascular risk factor profiles – ie., the percentage of people with two major risk factors, such as Type 2 diabetes, obesity, smoking and high blood pressure – were worse among those who lived longer than 15 years in Canada.

Canadians of Chinese descent showed the worst decline in heart health over time, followed by whites, blacks and South Asians.

The study also found smoking was a major risk factor for blacks and South Asians, especially females, living in Canada 15 years or more.

The study extended beyond examining the physical effects of being an immigrant in Canada over the longer term.

It also found higher psychosocial stress among South Asian females who had been residents for at least 15 years, although the researchers were uncertain about the reasons for that finding.

Heart disease incidence drops, risk factors rise

ICES notes that this study is the first to pinpoint which factors most likely contribute to the decline in heart health in each of Canada’s major ethnic groups.

The research found, for instance, that the Chinese and white individuals in the study who lived in Canada at least 15 years had a higher prevalence of diabetes than their recent immigrant counterparts. The researchers believe this finding is likely driven by much higher obesity rates among Chinese and white individuals who were longer-term residents.

As well, the cardiovascular dangers among the black and South Asian groups were mainly linked to their higher propensity to smoke – in fact, black and South Asian females who had lived in Canada for at least 15 years were three to four times more likely to smoke compared to their recent immigrant counterparts.    

The study concludes that advances in clinical and public health strategies have resulted in the reduction of cardiovascular disease incidence and mortality. But the rates of cardiovascular risk factors, namely obesity, diabetes and high blood pressure, continue to rise.

"Given that immigrants will be responsible for the net growth of the Canadian population by 2031, there is a need to better understand how we can preserve the healthy lifestyles and behaviours of recent immigrants and how we can reduce the negative influences of Western culture that causes health to deteriorate in long-term residents," it says.

"These study findings will enable us to be more responsive to the health-care needs facing different ethnic-immigrant groups in Ontario and will be critical in the development of cardiovascular disease prevention strategies and appropriate health-care delivery."