MONDAY, Sept. 28 (HealthDay News) -- Women with type 2 diabetes
have a 26 percent increased risk of developing atrial fibrillation, a
potentially life-threatening irregular heartbeat, new findings
suggest.

The overall incidence of atrial fibrillation was 3.6 percent among
people with type 2 diabetes, while the rate for people without the
metabolic condition was only 2.5 percent, according to the study, which
will be published in the October issue of Diabetes Care.

"We found that people with diabetes have about a 44 percent higher
prevalence of atrial fibrillation," said study author Gregory Nichols, an
investigator at Kaiser Permanente Center for Health Research in Portland,
Ore. "When we stratified the data by sex, the association was still
elevated for men -- but not statistically significant -- but for women, it
was still statistically significant."

The researchers were not able to tease out from the data in this study
why women with diabetes might have a higher rate of atrial fibrillation.
The authors theorize that diabetes may affect the cardiac autonomic nerves
in much the same way the disease damages peripheral nerves and causes a
condition known as peripheral neuropathy.

Not everyone is convinced that cardiac neuropathy is to blame, however.
"In people with diabetes, the cluster of other cardiac risk factors, like
obesity and hypertension, increases the risk of atrial fibrillation," said
Dr. Howard Weintraub, clinical director of the Center for the Prevention
of Cardiovascular Disease at the NYU Langone Medical Center in New York
City.

Diabetes is a known risk factor for heart disease. As many as 65
percent of people with diabetes will die from heart disease and stroke,
according to the American Diabetes Association. Death rates from heart
disease are up to four times higher for people with diabetes when compared
to people without diabetes.

The current study culled data from more than 10,000 members of an HMO
diabetes registry who had type 2 diabetes, and then matched them by age
and sex to more than 7,000 people without diabetes. The study period was
January 1999 through December 2008.

Over an average follow-up time of about seven years, people with type 2
diabetes developed 9.1 cases of atrial fibrillation per 1,000
person-years, according to the study. During the same period, there were
6.6 cases (per 1,000 person-years) of atrial fibrillation in people
without diabetes.

When the researchers adjusted the data to account for other factors,
such as obesity and high blood pressure, they found that the increased
risk of atrial fibrillation in people with type 2 diabetes only remained
for women.

Nichols said that this information is important for doctors to know
because they might not always look for atrial fibrillation in women.

But, he added, in this study, "among women, diabetes was a stronger
predictor of atrial fibrillation than obesity and elevated blood
pressure."

Weintraub pointed out that this study didn't include comparisons of
echocardiograms (an imaging test of the heart), which would have allowed
researchers to assess heart health at the start of the study, and ensure
that no one with preexisting, but undiagnosed, heart disease was included.
Additionally, the researchers didn't look to see if blood sugar control
made a difference in the rates of atrial fibrillation.

"Diabetes is a metabolic disorder in which heart disease risk factors
cluster," said Weintraub. He added that one important take-away message
from this study is to try to aggressively control your weight and blood
pressure levels, particularly if you have diabetes, because it increases
your risk of atrial fibrillation and other forms of heart disease.

More information

For more on heart disease and diabetes, as well as tips for improving
your cardiovascular health, visit the American Diabetes Association.