September 21, 2022

expert reaction to unpublished conference abstract about BMI vs waist-to-hip ratio

A conference abstract (not a published paper) presented at the Annual Meeting of the European Association for the Study of Diabetes looks at waist-to-hip ratio vs BMI as a predictor of all-cause mortality.

Prof Nick Finer, Honorary Clinical Professor at the National Centre for Cardiovascular Prevention and Outcomes, UCL Institute of Cardiovascular Science, said:

“It is well established that BMI is an imperfect measure of the risks of having overweight or obesity, and that many (not all) of these risks are driven not just by how much fat is stored in the body but where it is stored. It has been long known that the waist-hip ratio is more closely associated with mortality than body mass index, and for this reason is included in guidelines for the assessment and management of overweight and obesity.

“This research, using genetic methods, confirms that this relationship is causal – that is to say this link is not just an association, but that a higher waist-hip ratio actually is the cause for loss of life expectancy.  However, there is a problem about relying on the waist-hip ratio as a measure of obesity severity, because it changes little with modest weight loss and so does not necessarily reflect health improvements as a result of obesity treatments that lead to weight loss.  

“While mortality is of course important, for many people living with obesity it is everyday symptoms such as painful joints, breathlessness, mood changes and being stigmatised that really impact on quality of life and may relate better to weight rather than fat distribution.  The findings do highlight the need for better clinical measures to assess obesity and its risks, and moving away from just considering weight alone.”

Prof Keith Frayn, Emeritus Professor of Human Metabolism, University of Oxford, said:

“The idea that fat distribution, as reflected in the WHR, is a better predictor of adverse health outcomes than the simple measure of BMI is an old one.  But the interpretation is not simple.  It’s not the case that people accumulate fat either around the waist or on the hips.  The two go together.  People with a low WHR but high BMI are rare.  The simple message should be not to accumulate too much fat, wherever it goes.”

‘Waist-to-hip ratio is a stronger, more consistent predictor of all-cause mortality than BMI’ by I. Khan et al. was presented at the Annual Meeting of the European Association for the Study of Diabetes 2022.

Declared interests

Prof Finer is medical director of WEMA, a company providing obesity treatment

Prof Frayn: “I have no conflict of interest to declare.”