BEIJING, Nov. 4 (Xinhuanet) -- Scientists say they've found a better way of measuring obesity and a person's risk of getting a heart attack than the method used by doctors worldwide for years.

    IT has long been thought that fat people are more at risk of a heart attack, but doctors say today that it is not as simple as that. It all depends on where the fat is. A large bottom and thighs could be positively healthy ¡ª a ¡°beer belly¡±, on the other hand, spells trouble, no matter how skinny the person may be elsewhere.

    Researchers reported in Friday¡¯s issue of The Lancet medical journal that a hip-to-waist ratio is a better predictor of the risk of heart attack for a variety of ethnic groups than body-mass index (BMI), the current standard.

    BMI (based on a person's weight and height) takes no notice of where a person's fat lies or how muscular that person may be, says Dr. Arya Sharma, co-author of the study and a professor of medicine at McMaster University in Hamilton, Ont.

    Therefore, a well-muscled athlete and an obese person could have similar BMI scores.

    A study of 27,000 people, including more than 14,000 heart disease patients, has found that waist-to-hip ratios can mark out those people more likely to suffer heart failure far more effectively than conventional tests.

    The findings are so siginficant because they show that it is a certain type of fat distribution undetectable by BMI tests that is particularly risky. Researchers found that people with excess abdominal fat were heart attack sufferers, while others could be generally overweight but at no greater risk.

    Arya Sharma, co-author and professor of medicine at McMaster University in Canada, told The Times: ¡°A lot of people who do not consider themselves as obese will find they are beyond the cut-off point. Fat on the abdomen is the killer, not fat on the hips.¡±

    How to calculate waist-to-hip ratio

    Figuring out your risk is simple. Using a tape measure:

    Measure your hips.
    Measure your waist. 
    Then divide the waist number by the hip number.
    For a healthy woman: the total should be under 0.85

    For a healthy man: the total should be below point 0.90

    (A 30-inch waist and 36-inch hips would work out to a favorable 0.83, or 83 percent.)

    (Agencies)