Waist Circumference Just As Important As BMI When It Comes to Understanding Obesity Risks

Waist circumference is an underused but useful "vital sign" of an individual's health. That's according to experts, who said losing weight in this area is an important way for people to reduce the risk of encountering health problems related to obesity.

In a consensus statement based on existing evidence published in the journal Nature Reviews Endocrinology, Robert Ross of Canada's Queen's University Lifestyle and Cardiometabolic Research Unit and 16 fellow experts called on healthcare professionals to routinely measure the waists of their patients, as this could help with protecting and managing their health.

Currently, body mass index (BMI) is commonly used to calculate whether a person has a healthy weight, by dividing their weight in kilograms by the square of their height in meters. While BMI gives a guide of health across populations, it isn't as helpful on an individual level.

That's because BMI, the scientists explained, doesn't reflect the distribution of weight, and particularly whether a person has fat on their abdomen. Measuring waist circumference, on the other hand, does. Regardless of a person's BMI, waist circumferences are "strongly" linked in scientific literature with dying of any condition, as well as from heart disease, the team said.

Decades of research suggests that combining the two measures paints a clearer picture of the health risks a person might face due to their weight, they said.

According to the U.S. Centers for Disease Control and Prevention, the latest figures show that 39.8 percent of adults in the U.S. are obese. The condition can raise a person's risk of developing heart disease, stroke, type 2 diabetes and certain types of cancer.

The experts cited several studies showing waist circumference has risen over the past few decades, including a study conducted in Canada between 1981 and 2007.

"The failure of BMI to detect such an increase in abdominal obesity confirms the limitations of BMI alone to identify the phenotype of obesity that conveys the greatest health risk," the authors of the statement wrote.

They said exercising regularly at a moderate intensity and/or changing diet can shrink the waistline.

Professor Jimmy Bell, an expert in obesity at the University of Westminster, U.K, who was not involved in the statement study, told Newsweek he agrees with the statement. "The scientific community has known this for a long time," he said.

Bell agreed BMI is not a sufficient measure of body fat and distribution. "Waist circumference goes some way into helping with this, but [is] still not very accurate." The gold standard is imaging techniques, but these are expensive and not readily available, he said.

The team's recommendations to improve waist circumference are "sound," he said, and have been shown to be effective.