Overweight Aboriginal Women at Dramatically Higher Risk for Gestational Diabetes

Posted July 03, 2002


FOR IMMEDIATE RELEASE - July 3, 2002 2002-07-01-ME

Overweight Aboriginal Women at Dramatically Higher Risk for Gestational
Diabetes

University of Saskatchewan researchers have found that overweight Aboriginal
women are almost five times more likely to develop gestational diabetes (GD)
than overweight non-Aboriginal women.

In a recently published study, Aboriginal women were also found to have
twice the risk of GD compared with women in the general population after
adjustment for other potential variables. Many pregnant Aboriginal women
with GD, as well as children of GD pregnancies, later develop Type 2
diabetes, a current epidemic in Aboriginal communities.

"This is the first time in Canada that Aboriginal women with and without GD
were directly compared to non-Aboriginal women," said Dr. Roland Dyck, lead
investigator on the study and a member of the U of S department of medicine
at Royal University Hospital (RUH).

"We have found that Aboriginal ethnicity is an independent risk factor for
GD, and GD could be a key factor in the Type 2 diabetes epidemic because of
its impact on the next generation."

While obesity alone does not account for the difference in GD risk, the
combination of Aboriginal ethnicity and obesity resulted in dramatically
higher levels of GD among Aboriginal women.

The team's research shows that almost 30 percent of Aboriginal women who are
obese before pregnancy develop GD, while fewer than five per cent of
overweight non-Aboriginal women develop GD. In contrast, the team found that
fewer than five per cent of Aboriginal women who are at a healthy weight
before pregnancy develop GD, compared to three per cent of non-Aboriginal
women.

GD develops during pregnancy when the placenta produces hormones that can
cause insulin resistance. This raises blood-sugar levels in both the mother
and fetus, and in infants, can cause high birth weight, difficult
deliveries, jaundice, and respiratory distress. These infants are also more
likely to develop diabetes as adults.

Dyck's team concludes that fitness and nutrition programs are urgently
needed for expectant Aboriginal mothers. He thinks exercise could
significantly reduce both GD and Type 2 diabetes. Regular physical activity
reduces insulin resistance and blood sugar levels, increases energy, and
helps to control weight gain. Increased fitness also contributes to easier
pregnancies and deliveries.

The study involved more than 2000 Saskatchewan women, of whom 252 were
Aboriginal. Findings were published in Diabetes Care, an American Diabetes
Association healthcare professional magazine.

Aboriginal obesity may be caused by a "thrifty genotype" -- a survival
mechanism that prepares for nutritional hardship by conserving calories when
food is abundant. This genotype may have contributed to healthier
pregnancies and births centuries ago. But now, when combined with high food
intake and decreased physical activity, it's a liability that leads to
increased rates of GD and Type 2 diabetes, says Dyck.

"This disease didn't exist in Aboriginal populations 60 years ago," he
says, referring to a 1937 Saskatchewan study conducted by Dr. Lillian Chase
that didn't turn up a single case of diabetes in a population of Registered
Indians. "Theoretically, there's no reason why the current epidemic can't
be turned around in another 60 years."

"As exposure to non-Aboriginal lifestyles increases, rates of obesity also
increase," said Dyck. "Genetics don't change in 50 years, or even over a
century. Lifestyles change."

The study was funded by U of S and Saskatoon District Health. Other U of S
researchers included epidemiologist Helena Klomp (medicine), and professors
Leonard Tan (community health and epidemiology), Roger Turnell (obstetrics
and gynecology), and Makram Boctor (medicine).

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For more information, contact:

Dr. Roland Dyck
Department of Medicine
University of Saskatchewan
Royal University Hospital
(306) 966-7947

Kathryn Warden
Research Communications Officer
University of Saskatchewan
(306) 966-2506
www.usask.ca/research