New, Shocking Study Finds Humans Are Not Standardized!

Folks here probably know about the BMI– and possibly are familiar with my, ahem, “issues” with it as a tool of diagnosis; anything that bases treatment choices on the assumption that bones, fat and muscle all weigh the same, and people are identically proportioned, is going to get me angry.  Add in it being changed in 2000 by over 2kg/m2 (so that “overweight” is 25kg/m2; BMI is weight in kg divided by height in meters, squared) to make it easier to calculate and remove the differences between men and women and…well, I’m getting distracted.

Anyways, the BMI is the basis for the “obesity epidemic” we’ve all heard about, and there are calls for action on the following theory that this generation will die earlier than their parents.

Shockingly, some scientist actually decided to do research to see if being over-weight or obese by this BMI standard resulted in dying earlier.  It’s clear that if you’re heavy enough, you do die earlier, but that’s diagnosis by examining actual people, not by applying a broad standardized calculation.

There’s a problem: they didn’t confirm what “everyone knows.”

The news will seem heaven sent to those contemplating a new year diet, and contradicts the received wisdom that being fat reduces life expectancy. It is the second time that research studies led by Katherine Flegal, a distinguished epidemiologist from the National Centre for Health Statistics at the Centres for Disease Control and Prevention in Maryland, US, have studied the link between obesity and mortality.

In 2007 the same group caused consternation among public health professionals when they published the results of a similar analysis that also showed being fat does not shorten life. Walter Willett, professor of nutrition at Harvard School of Public Health, dismissed the finding as “rubbish”.

Dr Flegal told The Independent she had decided to conduct a second, larger, study on the same theme to counter the sceptics. She and her team examined results from 100 studies from around the world, involving three million people and 270,000 deaths.

via Recipe for a long life: overweight people have LOWER death risk – Health News – Health & Families – The Independent.

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6 thoughts on “New, Shocking Study Finds Humans Are Not Standardized!”

  1. In this case, yeah….

    *considers stopping with that deliberate ambiguity*

    *grin*

    It’s worse than a social construct, it’s a bureaucratic construct!

  2. It’s pretty sad, especially since the same paper that promoted the use of BMI for population studies considered it “inappropriate for individual diagnosis”. The reason why it’s inappropriate is that it doesn’t actually simulate human body composition very well. In fact, I wonder if it’s appropriateness for population studies may not have waned since the 1972 paper. That was 30 years ago, plenty of time for population characteristics to change.

    Some fun BMI math, if you double all dimensions, mass increases proportionally by a factor of eight (as a function of increased volume and assuming constant density). So if you double all dimensions of a 2m, 100kg individual and plug the new numbers (4m, 800kg) into the BMI calculation, the BMI doubles. BMI is simply biased against taller people, although not actually so dramatically as in this example. Taller folk have generally narrower frames, meaning not all dimensions are increased in proportion. The appropriate exponent will be somewhere between 2 and 3, and ought to vary between these extremes based on an individual’s frame.

    In fact, it would be moderately interesting to compare population height from 1972 with height today with regards to BMI as a population measure. As the population trends taller, BMI will be less appropriate.

    And none of this even tracks symptoms of actual disease!

  3. Whoops, forgot to mention that this has been widely known in medical/scientific circles for years. Media is can’t report science/medicine worth a damn, and people who set policy depend more on media than on actual scientific understanding. The first paper I read observing this phenomenon was at least that long ago. Maybe even longer. Even our own study of cardiac function before and after gastric bypass took enrolling a LOT of patients to find a large enough cohort that had poor cardiac function.

    1. Medical, scientific, theological, technological…does media get anything reported very well?

      Other than the stuff it makes up entirely, like “hot Hollywood gossip.”

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