How height divided by waist adds up

By Lesley Dobson, Tuesday 15 May 2012

Finding out how likely we are to avoid certain conditions, and how to live a healthier and longer life, could be a question of simple mathematics
Measuring tapeResearch shows that your waist-to-height ratio is a good predictor of future cardiometabolic risk

First we had BMI (Body-Mass Index), as a means of checking whether we are a healthy weight for our height. Then came Waist Circumference, the measurement around your middle. This was seen as an improvement on BMI, as it shows how much fat you’re carrying around your waist. This is an important health factor as it increases your risk of a range of conditions, including heart disease, stroke, diabetes and some cancers.

Now there’s a new measurement on the block. New research shows that waist-to-height (WtHR) is a better predictor of future cardiometabolic risk (heart disease plus diabetes), than BMI and WC measurement. The research, carried out by Dr Margaret Ashwell of Ashwell Associates, and Oxford Brookes University, involved a review of 31 papers, involving around 300,000 people, from a number of ethnic groups.

The research looked at how well the different measurements were able to tell which of the adults in the surveys had risk factors for conditions such as Type 2 diabetes, high blood pressure, and cardiovascular outcomes (for instance, heart attacks). The results showed that the WtHR was a better method of screening for the risk factors that can lead to these conditions.

Dr Margaret Ashwell feels that using waist-circumference and BMI measurements makes things more complicated than they need to be, as they need different values to be considered for people from different ethnic backgrounds. Using weight to height ratio would be simpler, as it is a one-size-fits-all approach, which could be used world-wide. So keeping your waist measurement to less than half your height measurement can help to keep your risk factors down.

Taking these calculations a step further, Dr Ben Rickayzan and Professor Les Mayhew from the Cass Business School, City University, London, have looked at how following this advice can affect your life expectancy. They have estimated that a 30-year-old non-smoking man could reduce his life expectancy by up to 14 percent, if his WtHR is above 0.7, and by as much as one third if it is above 0.8. The ideal ration is 0.5 or below. Dr Ashwell says “Keeping your waist circumference to less than half your height can help increase life expectancy for every person in the world.”

These study findings were presented at the 19th European Congress on Obesity in Lyon, France on Saturday, May 12 2012.

Another study by researchers at Oxford University has found that the journey from food on your fork to fat on your waist can take as little as three hours. The study, by Professor Fredrik Karpe, and Emeritus Professor Keith Frayne, showed that fat eaten during a meal can enter our blood stream within an hour of being eaten.

Within three to four hours, most of that fat has been deposited in our adipose tissue, a lot of which is stored around our waists. In the paper, published in the journal Physiological Reviews, the scientists suggest that people who are fit find it easier to get rid of fat, as exercise improves their bodies’ fat-burning abilities.

If you would like to compare all three types of measurements, you can find out your BMI easily by using the BMI calculator on the NHS Choices website. For the other measurements you will only need a tape measure.

NHS Choices BMI Link

The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.


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