Waist-to-hip ratio may better predict early death than BMI, researchers say

• Body mass index is often used to measure health, but some doctors argue that it is not accurate.
• New research suggests a more useful way to assess disease risk is waist-to-hip ratio.
• Measuring where body fat is stored may indicate fat around the organs, linked to heart disease and type 2 diabetes.

Forget BMI — there may be a better way to assess your health risks through your body composition, according to new research presented at the annual meeting of the European Association for the Study of Diabetes.

Researchers from University College Cork and McMaster University in Canada analyzed data from more than 380,000 white residents in the UK, looking for links between high body fat, where that body fat was stored, and the risk of premature death.

They found that, consistent with previous research, higher levels of body fat were associated with a higher risk of premature death.

However, an even stronger association was found between health risks and a high waist-to-hip ratio, which is a more specific measure of fat stored around the abdominal area, including the organs.

An increase in waist-to-hip ratio was linked to nearly twice the increase in the risk of premature death as a comparable BMI measure, researchers found. And the association between waist-to-hip ratio and health risks was particularly strong for men.

The new research findings could help address an important limitation of trying to measure health risks using body mass index (BMI), the ratio of height to weight, according to Irfan Khan, the project’s lead researcher and a medical student at University College Cork.

“It doesn’t take into account where fat is stored – whether it accumulates around the hips or the waist. As a result, BMI does not reliably predict the risk of disease or death,” Khan said in a press release. “This could mean that someone who has accumulated fat around their waist will have the same BMI as someone of the same age and height who stores their fat around the hips, despite the health risks of belly fat.”

BMI has previously been criticized by some doctors for being an inaccurate measure of individual health because it doesn’t take into account other variations in weight, including genetics, muscle mass, and more.

In contrast, the waist-to-hip ratio may help indicate a higher percentage of belly fat, such as visceral fat, which, according to the researchers, is found around organs such as the heart. Large amounts of visceral fat around the heart and other organs are linked to an increased risk of heart disease and other potentially fatal conditions, regardless of BMI, previous research suggests.

As a result, a higher waist-to-hip ratio may identify people at higher risk for chronic disease, while a lower waist-to-hip ratio in the most recent study was associated with a lower risk of premature death, the researchers found. The new evidence could help deliver better care and improve outcomes for patients, Khan said.

“A more accurate measurement of healthy body shape can make a significant difference to the ill health and deaths caused by type 2 diabetes, heart disease, some cancers and a host of other conditions,” he said in the press release.