Women with diabetes are more likely to develop an irregular heart rhythm than
non-diabetics of either gender --and this increases their risk of stroke.
This is a key finding of a study published in the October issue of Diabetes
Care. Dr. Greg Nichols, the lead researcher for the seven-year study by the
Kaiser Permanente Center for Health Research in Portland, Ore., says: "Women
with diabetes have an increased risk of developing atrial fibrillation. We found
a highly statistically significant association for women, with diabetes being a
stronger risk factor for atrial fibrillation than obesity or raised blood
pressure."
The study, which involved the electronic health records of 35,000 people, showed
that, after adjusting for other risk factors, the risk for atrial fibrillation
was 26 per cent higher in women with diabetes. It is already known that
diabetics are more prone to heart disease than non-diabetics, but the study
results are "new in relation to atrial fibrillation," Nichols says.
Atrial fibrillation is the most common form of cardiac arrhythmia, affecting
more than 250,000 people in Canada and some three million in the U.S. A rapid,
irregular fluttering of the heart's beat caused by random electrical discharges,
it can trigger a stroke. The condition can allow blood to pool and clot in the
heart.
"What this study shows is that diabetes brings the risk of atrial fibrillation
for women up to that of a man's," Nichols says. "Diabetes is an enormous public
health problem and atrial fibrillation is the most common arrhythmia diagnosis.
The study shows the confluence of two epidemics, particularly for women."
Some 2.4 million Canadians and 285 million people worldwide have Type 2 diabetes
(once known as non-insulin-dependent diabetes mellitus or adult-onset diabetes).
By 2030, the World Health Organization predicts that the number will exceed 366
million and the International Diabetes Federation expects it to be even higher
at 435 million. Heart disease is likely to be the cause of death for 80 per cent
of diabetics.
Registered dietitian and diabetes educator Karen Butler of the
Metabolic&Diabetes Education Centre in Regina, Sask., says that not only is the
risk of cardio-vascular disease "much higher than in the non-diabetic
population, but women also lose the protection that they have when they are
pre-menopausal."
"It is not at all surprising that there is an issue here," said cardiologist Dr.
Michael Gollob of the University of Ottawa Heart Institute, who specializes in
electrophysiology and heads the Arrhythmia Research Lab affiliated with the
Institute's Canadian Cardiovascular Genetics Centre. "While atrial fibrillation
is not as serious a condition as diabetes mellitus, if the two come together,
there is no doubt that this compounds the risk for stroke."
Dr. David Fedida, the associate head of anesthesiology, pharmacology and
therapeutics at the University of British Columbia, notes that "this large study
corrected for all the things that we would normally associate with atrial
fibrillation such as hypertension, high blood pressure or smoking and accounted
for other risk factors with diabetes such as obesity. Yet that did not get rid
of all the differences between non-diabetic and diabetic women. There was still
an extra risk of 26 per cent for atrial fibrillation."
Nichols says that the study did not assess diabetes treatments or glycemic
control as risk factors.
Although the current observational study does not focus on why the risk of
atrial fibrillation increases so much more for women with diabetes than for men,
it does indicate a possible connection with autonomic neuropathy, says Fedida,
pointing to the nerve damage associated with diabetes.
"The study suggests that cardiac autonomic neuropathy is perhaps related to
excess development of atrial fibrillation in diabetic people. While that doesn't
explain why it occurs only in women, the study does point out that the
electro-physiological properties in the heart are different in women. That could
perhaps mean greater susceptibility to atrial fibrillation. It is a new
observation worthy of study."
The findings of the current study will have an immediate result for nurse
practitioner Natasha Prodan-Bhalla of the Heart Program for Women at the B.C.
Women's Hospital and Health Centre: "Just knowing this about atrial fibrillation
allows me to pay a little more attention to women's heart rhythm," she says.
"Because this research has shown it's more common in that population, if it is
at all irregular, I'm going to send patients for further testing right away."
Source : The Edmonton Journal
