A medical U-turn has cast doubt on warnings that being overweight and “apple-shaped” is especially dangerous to the heart.
Researchers who studied 220,000 adults found that fat concentrated around the waist did not increase the risk of heart attacks and strokes any more than general obesity.
Their findings contradict previous evidence that obese individuals with “apple-shaped” bodies are three times more likely to suffer a heart attack than those with other kinds of fat distribution.
The authors of the new research argue that earlier studies had delivered a misleading message because of design flaws.
Experts said the results should help end confusion over different international guidelines.
Obesity as measured by a person’s Body Mass Index, which relates weight and height, and is a known risk factor for heart disease.
But recent research has suggested that being fat around the middle is especially bad, increasing the risk over and above that resulting from having a high BMI.
Some experts have even challenged the usefulness of BMI as an assessment tool, arguing in favour of the tape measure instead.
The new investigation involved examining data from 58 studies which collectively monitored more than 220,000 adults for almost a decade.
During this period, more than 14,000 participants suffered a heart attack or stroke.
Analysis confirmed that obesity was a major risk factor for heart disease. But the risk remained the same whether worked out from BMI scores – calculated by dividing a person’s weight in kilograms by their height in metres squared – waist circumference, or waist-to-hip ratio.
Waist-to-hip ratio compares the distance around the hips and waist to assess levels of “central obesity”. It shows if a person is “apple-shaped” with a bulging middle or “pear-shaped” with a narrower waist and fatter hips and bottom.
A consortium of 200 scientists from 17 countries carried out the study, funded by the Medical Research Council (MRC) and British Heart Foundation (BHF). The findings are published today in The Lancet medical journal online.
The authors, led by John Danesh, professor from Cambridge University, wrote: “Whether assessed singly or in combination, body-mass index, waist circumference, and waist-to-hip ratio do not improve prediction of first-onset cardiovascular disease when additional information exists on blood pressure, history of diabetes, and cholesterol measures. This finding applies to a wide range of circumstances and clinically relevant subgroups.”
Mike Knapton, associate medical director at the BHF, said: “Regardless of how you measure it, being obese is bad for your heart. This study suggests that measuring your waist is no better than calculating your BMI but it’s not time to throw away the tape measure just yet.”