Men who carry most of their fat in the belt area may be at increased risk of suffering a fatal Stroke, new research suggests.

Excess weight and obesity are established risk factors for Heart disease and Stroke, but the new study adds to evidence that the location of the extra pounds may be a key factor.

The study, which followed more than 9,100 Israeli men for 23 years, found that those who carried their excess fat mainly around the middle were at greater risk of dying from a stroke than those with more evenly distributed fat stores.

The effect of abdominal fat on stroke risk was seen regardless of a man’s body mass index (BMI), a measure of weight that takes a person’s height into account.

BMI, however, is not a perfect measure, the authors of the new study point out. For example, a very muscular person with a normal amount of body fat can have a high BMI, while someone with excess fat but little muscle mass could fall into the normal BMI category.

In the current study, a more specific measure of abdominal fat turned out to be a better predictor of stroke than BMI was, said lead author Dr. David Tanne.

“It is not only the presence of body fat that affects stroke risk, but also its distribution,” said Tanne, of Tel-Aviv University and the Chami Sheba Medical Center in Tel-Hashomer, Israel.

He and his colleagues report the findings in the American Heart Association’s journal Stroke.

The study included 9,151 men who were at least 40 years old at the time of recruitment in the 1960s. At the outset, researchers recorded the men’s weight and height, and gauged their body fat using two methods: a skinfold test that took one measure of fat in the torso, and one that assessed the ratio of body fat in the trunk compared with the rest of the body.

The latter test, which measured fat in both the trunk and the back of the arm, helps define where people carry their fat.

Over the next 23 years, 316 study participants died of a stroke. A man’s risk of having a fatal stroke rose in tandem with his BMI at the study’s start. However, his level of abdominal fat, in particular, was a stronger predictor of stroke risk.

Men with the greatest disparity between abdominal fat and fat in the rest of the body - that is, those with abdominal obesity - were 50 percent more likely to die of a stroke than men with the most even distribution of body fat.

Abdominal fat may be a particular health threat because of its link to the so-called metabolic syndrome, which is marked by high blood pressure, elevated “bad” cholesterol levels and impaired sensitivity to the hormone insulin, which regulates blood sugar. As trunk fat increases, Tanne explained, so do the risks of each of these disorders.

In addition, he noted, people with abdominal Obesity tend to show higher levels of inflammatory substances in the blood. Persistent inflammation in the blood vessels is thought to contribute to artery disease, Heart attack and stroke.

BMI has its “shortcomings” when it comes to gauging a person’s health risks, Tanne concluded. Simple measures that zero in on abdominal fat - including waist circumference and the waist-to-hip ratio - may be better indicators, he said.

SOURCE: Stroke, May 2005.