New research is challenging previous medical notions that "apple-shaped" people with more fat around their waist are at higher risk of heart attacks and strokes than "pear-shaped" people with fatter bottoms and hips.

A study of 220,000 people published on Friday confirmed that being obese -having a body mass index (BMI) of 30 or more - is a major risk factor for heart disease, but found the distribution of fat on the body has no impact on that risk.

"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," says Mike Knapton, associate medical director at the British Heart Foundation charity, which part-funded the study.