The rate of diabetes among aboriginal women is four times that of women in the general Canadian population, a new study reveals.
Moreover, members of first nations are developing the debilitating illness by their 40s, while in the rest of society it tends to strike people in their 70s.
"Diabetes is a disease of young first-nations adults with a marked predilection for women," said lead author Roland Dyck of the department of community health and epidemiology at the University of Saskatchewan.
"In contrast, diabetes is a disease of aging non-first-nations adults that is more common in men," he said.
Dr. Dyck said the big difference in the age of onset has serious implications; diabetes is one of the principal causes of blindness, amputations, kidney failure and heart disease.
The study, published in the Canadian Medical Association Journal, examined trends among patients diagnosed with diabetes in Saskatchewan from 1980 to 2005. The sample included 8,275 aboriginal people and 82,306 non-aboriginals.
The data paint a troubling picture of an unrelenting diabetes epidemic in native communities that "is likely to continue increasing in the foreseeable future," the paper notes.
Dr. Dyck and his team found that in 2005, 20 per cent of women and 16 per cent of men living in native communities had Type 2 diabetes. That was up sharply from 9.5 per cent and 4.9 per cent respectively in 1980.
Rates of diabetes in the non-aboriginal population rose to 5.5 per cent from 2 per cent in women over the same period, and to 6.2 per cent from 2 per cent in men.
Over all, the incidence (the frequency of development of diabetes in a population over a given time period) and the prevalence (the number of people currently suffering from the disease) were both about four times higher among aboriginal women and 2.5 times higher among aboriginal men.
The epidemiological study was not designed to explain the underlying causes of this disparity, but Dr. Dyck put forth a couple of likely explanations.
First, it has been well documented that rates of overweight and obesity are significantly higher in native communities. (Excess weight, particularly in the abdominal area, is a key factor in Type 2 diabetes.) In aboriginal communities, women are more likely to be overweight or obese than men, and at a younger age.
Second, there are high rates of gestational diabetes in pregnant aboriginal women. Those who develop diabetes during pregnancy are at high risk of developing Type 2 diabetes later in life, and so are their children.
"Gestational diabetes has been implicated in the intergenerational 'vicious cycle' by increasing diabetes among the offspring," Dr. Dyck said.
He added that the differences in the epidemiology of the disease in native and non-native people means prevention programs should be different as well.
In particular, programs for first nations should focus on women in their reproductive years and on preventing gestational diabetes, Dr. Dyck said.
There are three distinct forms of diabetes: Gestational diabetes is a temporary condition that occurs during pregnancy; Type 1 diabetes, usually diagnosed in children, occurs when the pancreas is unable to produce insulin; Type 2 diabetes occurs when the pancreas does not produce enough insulin, or the body does not effectively use the insulin it produces.
About 90 per cent of diabetics have Type 2 disease, which is usually a consequence of obesity, inactivity, poor diet and aging. Poverty is also strongly associated with diabetes, which could be another factor that helps explain high rates in native communities.