A woman with a waist of over 88cm is at highest risk of disease

The National Obesity Forum says 80% of people in a survey across 27 countries were unaware it was linked to diabetes.

Three quarters of 100 UK GPs questioned knew abdominal obesity was a risk factor for heart disease and diabetes.

But only 18% of patients at risk of these diseases said they had had their waists measured.

HOW TO CHECK Note - it is different to belt size Take off your shirt and loosen your belt Place a tape measure at a point 1cm below the tummy button Measure the waist circumference while breathing out, with the abdomen relaxed

And just 40% of the 615 people surveyed in the UK do not know that carrying fat around your stomach area increases the risk of heart disease

UK adults were surveyed as part of a Shape of the Nations study of the views of 6,476 participants in 27 countries, commissioned by the pharmaceutical company Sanofi-Aventis and backed by the World Heart Federation.

'Overlooked'

Having an abdominal circumference of more than 88 cm (35 inches) in women and 102 cm (40 inches) in men indicates the highest risk of cardiovascular and metabolic disease.

There is an increased risk of the diseases for women with measurements of more than 80cm and men whose measurement is over 94cm.

The National Obesity Forum estimates a third of British adults will be "abdominally obese" by the end of the next decade.

Dr Ian Campbell, president of the UK's National Obesity Forum, said: "We are facing a public health time bomb and can't afford to be complacent about waist size.

He added: "We want to encourage ministers to take action by pushing abdominal obesity higher up the healthcare agenda.

"Measuring waist circumference is a simple way to help identify patients at higher risk of heart disease and diabetes, yet as the survey shows, waist size gets overlooked by many of my fellow colleagues."