Being an apple 'no worse for health' than being a pear
Published 11/03/2011 | 16:10
Being an 'apple' shape is no less healthy than being a 'pear', according to a new study that turns the long-held belief on its head.
Doctors have long thought that people with an 'apple' figure - a tendency to store fat around the belly rather than the hips - were at a higher risk of heart disease and stroke.
In 2005 a study seemed to confirm that idea.
It found that having a higher waist-to-hip ratio - in other words being an 'apple' - was three times more powerful an indicator of heart attack risk, than simply being overweight.
Dr Arya Sharma, director of the Canadian Obesity Network, who led that study, said it would lead to doctors "forgetting about their scales and taking out their tape measures".
But now an analysis of records from 220,000 people in 58 studies, each monitored for over a decade, has cast doubt on this finding.
It discovered that having a higher waist-to-hip ratio was no better a predictor of heart disease and stroke risk than being generally overweight, as measured by body mass index (BMI).
BMI is calculated by dividing one's weight in kilograms by the square of one's height in metres.
The international group of scientists, led by Cambridge University, concluded in The Lancet that their findings "reliably refute" previous recommendations to measure waist-to-hip ratios rather than BMI.
"We have shown that BMI, waist circumference, and waist-to-hip ratio each have a similar strength of association with cardiovascular disease risk," they wrote.
Furthermore, the new study found that the really powerful indicators were not body weight or shape at all, but what was going on in the blood.
Once blood pressure, a history of diabetes and cholesterol levels were taken into account, neither body weight or shape added much in terms of predicting a cardiovascular event.
Researchers at Cambridge University's Cardiovascular Epidemiology Unit said: "This study shows that measuring your waist is no better for calculating your cardiovascular risk than calculating your BMI.
"It underlines the value of GPs continuing to measure cholesterol and blood pressure levels, irrespective of body shape."
However, they emphasised that being overweight or obese was still "the main risk factor for heart disease which can of course be influenced by lifestyle choices."
The authors believe that previous studies could have been affected by selection bias and reverse causality - when cause and effect are mixed up.
But Dr Mike Knapton, associate medical director at the British Heart Foundation, which co-funded the study with the Medical Research Council, said it was "not time to throw away the tape measure just yet".
Being overweight and having high cholesterol and blood pressure often went hand-in-hand, he said, so gauging a person's weight was a useful initial "screen" of whether they might go on to suffer heart disease or stroke.
And he still thought there was some truth in the 'apple' maxim. He said: "Abdominal fat seems to be associated with other risk factors for heart disease like raised blood pressure, cholesterol, a type of lipid and diabetes".