Waist-to-Hip Ratio May Be Better Indicator of Wellness Than BMI

A woman measures her waist with a tape measure.
Igor Alecsander/Getty Images
  • New research concludes that your waist-to-hip ratio could be a better indicator of health than BMI.
  • BMI is a widespread but controversial screening tool for obesity and overweight.
  • Experts interviewed by Healthline had mixed opinions about the significance of waist-to-hip ratio.

If you’ve been in for a checkup in the past year, chances are you know your Body Mass Index (BMI). But, what about your waist-to-hip ratio?

New research suggests that waist-to-hip ratio could be a simpler, more accurate indicator of weight and general wellness than BMI.

In a study published September 20 in the medical journal JAMA Network Open, researchers looked at a group of nearly 400,000 individuals to see whether BMI or waist-to-hip ratio (WHR) was a more accurate predictor of serious adverse health outcomes including cancer, cardiovascular disease, and death.

Their conclusion: “WHR had the strongest and most consistent association with mortality irrespective of BMI.” Furthermore, they believe that their findings have implications for the doctors’ office too, arguing that using WHR as a primary measurement of health could lead to better outcomes than BMI alone.

“We are interested in understanding what are the risk factors for cardio-metabolic diseases and how best to assess them. For this specific project, we aimed to determine what is the best way to assess adiposity,” Dr. Guillaume Paré, MD, a Professor of Medicine at McMaster University and lead author of the research, told Healthline.

“These findings support the increasing body of literature that have shown WHR to be superior to BMI, and suggest WHR should be used clinically,” he said.

BMI vs waist-to-hip ratio

For the study, Paré utilized the UK Biobank, a medical research database containing anonymous health and lifestyle information about its participants. Participants included 387,672 participants in the United Kingdom with an average age of around 60 years old.

Researchers used Mendelian Randomization, which uses genetics to help account for inherent predisposition for things like cardiovascular disease and cancer.

When comparing BMI and WHR to all-cause mortality, they found that BMI followed a “J-shaped association,” whereas WHR had a direct linear association. What that means in its simplest form is that every increase in WHR led to worse health outcomes no matter your BMI. Whereas BMI had worse outcomes at lower ranges, then improved in the middle (healthy BMI range), before once again worsening as BMI entered overweight and obese levels.

Paré and his team argue that WHR offers a simple, easy-to-read measurement that is also accurate. Unlike BMI where there is a healthy range, a WHR score should be as low as possible. Common guidelines suggest a WHR of < 0.95 in men and < 0.80 in women.

“Our research shows that the lower the better. We didn’t find a limit where no additional benefit was seen,” Dr. Paré told Healthline.

Some experts disagree

However, the suggestion that WHR is more accurate than BMI was disputed by other experts contacted by Healthline.

Dr. Maya Mathur, Phd, an Assistant Professor of Quantitative Sciences Unit at Stanford School of Medicine, commended the study for its strong sample size and use of Mendelian Randomization to account for genetic factors, but ultimately disagreed with its conclusions.

“I do think some of the conclusions of this new study are potentially misleading,” she told Healthline.

“BMI was just as good as WHR at predicting all-cause mortality for women (though not for men). This means that if the BMI association had been properly estimated by accounting for its nonlinear effects, BMI would almost certainly be a better predictor than WHR for women specifically,” she said.

Dr. Kuldeep Singh, Medical Director of bariatric services at Mercy Hospital in Baltimore, told Healthline that WHR is important, but said that BMI remains a more accurate and reliable measurement.

“The reason WHR has not replaced BMI is two fold: One is that BMI is the tested and a known parameter around which all medical research has been done. Number two is that BMI is very easy to calculate. Although waist to hip ratio is not difficult to calculate, there can be discrepancies in how it is measured and where it is measured,” he told Healthline.

BMI remains controversial

The prevalence of obesity has nearly tripled globally since 1975. One-third of the world’s population is now considered obese. These statistics are based on BMI, one of the simplest and most widespread health indicators used by doctors today. BMI is determined by a relatively simple equation: take your weight and divide it by your height squared.

Being overweight and obese according to your BMI has well-established associations with lots of bad things, including heart disease, cancer and death. 

But, despite its widespread use, BMI remains controversial.

Critics of BMI as a primary health measurement raise several important points: 

  • BMI doesn’t account for differences in body type. If you’re muscular but weigh more than you should, you would still be considered overweight or obese despite your fitness level.
  • There are established ethnic differences for BMI. Asian people in particular are more sensitive to changes in BMI than caucasians.
  • BMI doesn’t consider fat distribution on the body. Those with fat stored around their stomach area have a greater risk of chronic disease than those with fat stored in their hips, buttocks, and thighs.

How to take your WHR

A moderate WHR may be < 0.9 in men and < 0.85 in women or less, according to the World Health Organization.

Your waist circumference should be smaller than your hip circumference.

To find your WHR use a measuring tape and do the following:

  • Find the top of your hip bone and the bottom of your rib cage.
  • Halfway between these points is your waistline.
  • The belly button is often, but not always an indicator of the waist line area. 
  • This should be the smallest point around your abdomen.
  • Next take your hip measurement by measuring across the widest part of your hips and buttocks.

Once you have these two measurements divide your waist circumference by your hip circumference. This is your WHR.

The bottom line

New research concludes that waist-to-hip ratio or only waist circumference are simple and accurate health measurement that could potentially displace the use of BMI in the doctors’ office.

Waist-to-hip ratio showed a clear linear association with adverse health outcomes like cardiovascular disease, cancer, and death.

Other experts content that BMI is still an important, simple, and accurate measurement compared to waist-to-hip ratio.

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