Recent immigrants, particularly those of South Asian and African origin, are at high risk of developing type 2 diabetes compared with long-term residents of Ontario.

In the largest study of its kind in Canada, researchers at the Institute for Clinical Evaluative Sciences (ICES) and St. Michael's Hospital in Toronto found immigrants from South Asia had about twice the risk of developing diabetes than the rest of the Ontario population.

Roughly 12 per cent of the entire South Asian community that immigrated to Ontario in the previous 20 years had diabetes, the study found. That translates into more than 28,000 diagnoses among South Asian immigrants as of 2005.

The study of more than one million immigrants to Ontario between 1985 and 2000 also found:

  • Nearly 100,000 immigrants from all regions had been diagnosed with diabetes by 2005.
  • In all of Canada, men typically have higher rates of diabetes than women. However among immigrants, women had a 24 per cent and immigrant men had a 10 per cent higher rate of diabetes than other Ontarians.
  • The risk of diabetes differed by country of birth. Immigrants from South Asia were three to four times more likely to be diagnosed than immigrants from Western European countries, the researchers found.
  • Men and women from Latin America and the Caribbean had more than double the risk of Western European immigrants.
  • Increased risk for many immigrant groups started at an early age (35-49) – a full decade earlier than in the general Ontario population.

As for why immigrants had higher diabetes risk that other Ontarians, the researchers made a number of interesting findings. For example, they noted that lower socioeconomic status was associated with increased diabetes risk.

As well, the longer immigrants lived in Canada, the higher their risk of developing diabetes. Immigrants living in Canada for 15 years or more had a risk that was 1.5 times higher than immigrants who had lived in Canada only five to nine years.

"Recent immigrants, particularly women and immigrants of South Asian and African origin, are at high risk for diabetes compared with long-term residents of Ontario," writes Marisa Creatore, Epidemiologist at St. Michael's Hospital, Toronto, and her co-authors in the study, which appears in the Canadian Medical Association Journal.

"This risk becomes evident at an early age, suggesting that effective programs for prevention of diabetes should be developed and targeted to all immigrants in all age groups."

The authors conclude that lifestyle interventions aimed at recent immigrants should be explored further and that policy makers and planners should develop specific screening guidelines and community-level targeted diabetes educational programs.