People who carry fat around the middle of their body are at significantly greater risk of dying from cardiovascular disease even if they are a "healthy" weight, according to a new Australian study.
The study published in the Annals of Internal Medicine shows diagnosis of obesity cannot rely solely on a person's body mass index (BMI), says study co-author Emmanuel Stamatakis, an associate professor at the University of Sydney.
People of normal weight according to their BMI but who carry too much fat around the middle of their body are 22 per cent more likely to prematurely die from any cause and have a 25 per cent higher risk of cardiovascular disease compared with those who have small waistlines.
There are a range of reasons why a large waist circumference increases a person's risk of death, Prof Stamatakis says.
"We cannot be absolutely certain about the exact mechanisms but we do know that excessive fat around the waist is associated with insulin resistance, abnormal lipids profile (blood fats) and increased systemic inflammation," he said.
A person's BMI is calculated by dividing a person's weight by the square of their height and is commonly used to determine whether a person is overweight or obese.
However, it does not take into account waist circumference or hip-to-waist ratio - factors Prof Stamatakis says are "crucial" in measuring obesity.
"If I had to choose between making sure my BMI or my waist-to-hip ratio are within 'normal' range, I would go for the latter," he said.
BMI can be confounded by many things, including gender and a person's fitness.
"A well-trained individual can easily be classified as overweight even though their body fat content is in the very healthy range," Prof Stamatakis said.
"On the other hand, a high waist-to-hip ratio most likely means high amounts of abdominal fat and we know this comes with quite serious health risks."
