Originally Posted by SSP
It keeps getting mentioned because it's used in many scientific studies, and appears to be related to increased risk of mortality. It's not "irrelevant" to the many scientists who study these issues.
For instance, the New England Journal of Medicine published a
study in October, '99 in which
one million subjects were tracked over
14 years. They found a direct correlation between increasing BMI's and increased risk of mortality. Specifically, they found:
The risk of death from all causes, cardiovascular disease, cancer, or other diseases increases throughout the range of moderate and severe overweight for both men and women in all age groups.
In healthy people who had never smoked, the nadir of the curve for body-mass index and mortality was found at a body-mass index of 23.5 to 24.9 in men and 22.0 to 23.4 in women.
Actually, this conclusion is coming under increased scrutiney. I have read that most of the increase of mortality with obesity occurs 1) at the really obese levels and 2) is caused by cardio problems. With the new treatments for cardiovascular disease, the rates of death from cardiovascular disease are far lower and the negative effects of obesity are lower. Of course, risk from cardio vascular disease is not about weight per se, it is more about diet. There probably is some correlation between diet and BMI but it is not that big a thing.
Interestingly enough, recent studies seem to show that active and mildly over weight people are healthier than inactive skinny people.
The recent studies seem to show that there is no simple correlation between health risk and BMI. There is an increase in health risk if one is morbidly obese.
Another problem with BMI is that muscular, fit and relatively lean people can test out as being "obese" on the BMI. Some people, especially body builders can be very lean such as 4% body fat and still considered "obese" by the BMI. It really does not make any sense.