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If left untreated, high blood glucose levels over a long period of time can lead to complications like blindness and heart disease.

Type 2 diabetes in some women is linked to low household income and education, a Canadian report suggests.

Excess weight is well established as a risk factor for Type 2 diabetes. But while factors like excess weight and ethno-cultural origin played a role in who develops diabetes in both income groups, women in poorer households were significantly more likely to develop Type 2 diabetes, suggests the Statistics Canada report released Wednesday.

The study, "The role of socio-economic status in the incidence of diabetes," tracked the health of more than 17,000 Canadians since 1994-95.

For women, a "modest" link between Type 2 diabetes and lower education persisted among those who had only secondary education compared with post-secondary schooling, Heather Gilmour of the agency's health analysis division and her co-authors found.

The link was weaker once excessive weight, obesity and aboriginal or South/Southeast Asian ethno-cultural background were considered, the report's authors said.

Among men, the association between the condition and lower education disappeared once weight and behavioural factors like smoking, drinking and lack of exercise were taken into account.

Male, female difference

Health research often focuses on factors like weight, smoking or physical activity, but this study is important because it highlights the influence of broad social factors like income and education that might shape people's health, said Spencer Moore, a professor at Queen's University in Kingston, Ont.

As for why the findings may differ between men and women, Moore pointed to the challenge of using self-reported measures of body weight or physical activity rather than measuring these directly.

"If as other studies have shown, women are more likely to under-report their weight compared to men, then the study may be underestimating the influence of weight status on women's risk," said Moore, at Queen's school of kinesiology and health studies.

The report also doesn't take diet into account.

In June, Type 2 diabetes researchers at Toronto's Institute for Clinical Evaluative Sciences said women in Ontario with a low income are more likely to be obese or overweight than high-income women, whereas men have less difference in BMI across income groups.

For women, the findings suggest that more highly targeted prevention strategies are needed, the study's authors concluded.

In Type 2 diabetes, the pancreas produces insulin, but the body becomes resistant to its effects.

Rising prevalence

The 15-year study is based on a sample of 5,547 women and 6,786 men 18 or older who responded to the National Population Health Survey.

Among those who had been free of diabetes in 1994-95, the study found 7.2 per cent of men and 6.3 per cent of women had either developed the disease or died from it by 2008-09.

More than three million Canadians have diabetes, and 90 per cent of those have Type 2, according to the Canadian Diabetes Association.

In December, a report by the association predicted the number of people diagnosed with diabetes in Canada is expected to nearly double between 2000 and 2010, from 1.3 million to 2.5 million.

The disease is expected to cost Canada nearly $17 billion by 2020, up from more than $10 billion in 2000, expressed in 2005 dollars.