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CONTROVERSY: WHAT IS THE
CONNEXION BETWEEN OVERWEIGHT AND MORTALITY?
It is well known that obesity
leads to a higher occurence of a set of diseases and shortens life expectancy.
But what are the exact figures? Ever since the well reported surveys from the so
called Framingham group (United Kingdom), it is known as a fact that
cardio-vascular diseases and diabetes mellitus have a higher prevalence in
merely overweight patients (Body Mass Index above 25 kg/square meter).
The famous American journal JAMA
wonders about the variations and discrepancies underlying the figures that have
been published lately according to different épidemiological studies between
1999 and 2005. A first paper reached the conclusion that 112 000 deaths could be
attributed to obesity in 2000 in the United States, whereas two other authors
had an estimate of 414 000, or 280 000 in an anterior period of time
(1991). Wher does such a gap come from ?
Statistical models are debated among physicians dealing with public health issues.
As a matter of fact, one should take into account the prevalence of obesity as
a risk factor, and the scale of its connexion with the causes of
premature deaths (which is called "relative risk"). Some variables create an interference with
the results: the correlation with other risk factors has changed (for exemple
most obese people are not any more important smokers), or the population aging
process, that entails a relative weight decrease whilst obesity affected a
significant part of the anterior life...
* Deaths attributable to
obesity. DH Mark. JAMA 2005; 293: 1918-9.
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