London - At last, here’s something for women with bigger bottoms to smile about. Research shows they live longer.

A study has found that pear-shaped women, typified by the small waists and shapely bottom of the likes of Kate Winslet and Christina Hendricks, have a longer life expectancy than the apple shapes who store fat around their middle.

What is more, the figures are far from trivial. A 30-year-old woman who is a perfect pear is expected to live up to nine-and-a-half years longer than one whose waistline wobbles. The projections for men are even more stark, with a 30-year-old with a huge beer belly forecast to die almost 17 years before a chap with a washboard stomach, the European Congress on Obesity in Liverpool heard.

Margaret Ashwell, the former government adviser who carried out the analysis, said the real killer is not just fat but the flab found around the middle.

Although a lot of it is hidden from sight, it is wrapped around the organs and produces hormones and other substances that tamper with blood pressure, cholesterol and blood sugar levels.

As a result it raises the risk of a host of health problems including heart disease, diabetes and strokes.

For this reason, Dr Ashwell, who worked with mathematicians from London’s City University, says it is crucial it is factored in when working out how bad a person’s weight is for their health.

Doctors generally use body mass index, or BMI, a mathematical formula based on a person’s weight and height to work out whether they are in good shape.

However, BMI doesn’t distinguish between muscle and fat, meaning some athletes are classified as obese. Dr Ashwell advocates looking at waist measurement in comparison to height. As a rule of thumb, she says, we should aim to keep our waist circumference measurement to under half that of our height – or have a waist to height ratio of 0.5 or less.

So, a woman who is 5ft 4in should try to keep her waist at 32in or smaller and a man who is 5ft 10in shouldn’t let his waistband exceed 35in.

Any bigger than this and their shape starts to turn from pear-like to apple-like.

By analysing 20 years of data on around 3 000 men and women from across the UK, Dr Ashwell has shown that waist-to-height ratio is a better predictor of life expectancy than BMI.

She said: “By using waist-to-height ratio, you are measuring the central fat and that’s the bad fat, so therefore you are getting a handle on how bad things are.”

And, by mapping age of death alongside waist and height measurements, she has been able to work out how many years a bulging belly takes off a person’s life.

Dr Ashwell, who runs an independent scientific consultancy, said: “This study supports the simple message ‘Keep your waist circumference to less than half your height’. The use of weight-to-height ratio in public health screening, with appropriate action, could help add years to life.

“If health professionals included this simple measurement in screening procedures, many years of productive life could be saved.”

She added that apple-shaped men and women should not despair, however, because fat around the waist is usually the first to melt away when we diet.

Professor Jason Halford, of the UK Association for the Study of Obesity, said: “I think we are beginning to realise BMI is not the only measure we should be concentrating on.”

However, he warned it takes time to prove the worth of new weight measurement techniques. - Daily Mail