The Math of Measuring Obesity: Research in Progress

math of obesityThe BMI (Body Mass Index) – the measurement most commonly associated with obesity – has been used since the mid-1800’s, but has long been regarded to have major flaws. These flaws include: a disregard for body composition, resulting in highly muscular people often having BMI’s that wrongly indicate obesity; additional inaccuracies when measuring children, elderly, thin individuals, or people of certain races; and low accuracy as a predictor of health issues such as cardiac disease and diabetes. More recently, Waist to Hip Ration (WHR) has been used as an indicator of health and risk of disease. WHR is the primary measure that takes into account the shape of the person – most commonly referred to as apple vs. pear – as opposed to the composition of their body.

A presentation was given at ASMBS 2011 on a potential new way to measure obesity. Dr. Wohlgemuth talked about his work over the last few years, and attempts at creating a new, more accurate and helpful measure of obesity and health risk. One of these recent attempts is a Total Volume to Surface Area (TV/SA) ratio. Through studies using a full body scanner, scientists looked at what happens to this ratio as a person becomes more obese. They found that the more obese you are, the more your TV/SA ratio increases.

Another attempt was the Primary Shape Indicator, which is the ratio of a person’s volume in the upper half of their body to the volume in the lower half of their body. The deliniation between ‘upper half’ and ‘lower half’ is determined by the line/section of their body that has the maximum volume (“torso max point”). Traditional inputs such as height and weight have been combined with inputs from a 3D full-body scanner, to look at both the TV/SA ratio and the Primary Shape Indicator.

The most recent measure these scientists looked at is called Current Adiposity Index. Current Adiposity Index gives the concentration of a person’s weight relative to that person’s “excess volume”. This leads to a measure called Central Obesity Tendency (COT) which is the Central Adiposity Index / Shape Tendency). They found that the higher the COT, the more centrally obese the person is. A comparison between Metabolic Syndrome and COT shows statistically significant results.

This measurement is in the early stages of study, but shows promising results when looking at its potential correlation with certain major obesity-related health issues.

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