Diabetes in women linked to irregular heart rhythm: study
Reported November 10, 2009
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