TCS Daily


Whoppers and the End of an Epidemic

By John Luik - April 22, 2005 12:00 AM

It isn't just that they were fudging the numbers, it is the scope of the fudging that is so breathtaking. For the last few years Americans have been subjected to an incessant barrage of warnings about the risks of dying from being fat. The most dramatic of these came last year in a study from the US Centers for Disease Control that suggested that some 400,000 lives were lost each year due to obesity and that obesity related mortality would soon overtake tobacco as the leading cause of death in the US.

But in a study released this week by the CDC and published in the Journal of the American Medical Association ("Excess Deaths Associated with Underweight, Overweight, and Obesity"), the public health community has finally owned up to their massive fib by acknowledging that the number of deaths due to obesity in the US is closer to 26,000 not 400,000 as previously reported. This means that if these numbers are correct -- which is questionable -- then obesity goes from being the leading or second leading cause of death to perhaps the seventh leading source of premature mortality.

Apart from this huge downward revision in the numbers of people supposedly dying from fat, there are several things in this study which signal the end of any legitimate linkage between obesity and premature death. First, for the merely overweight with BMI's from 25-30 there is no excess mortality. In fact, being overweight was "associated with a slight reduction in mortality relative to the normal weight category." Being overweight not only does not lead to premature death, something that dozens of other studies from around the world have been saying for the last 30 years, but it also carries less risk from premature death than being "normal" weight. In other words the overweight=early death "fact" proclaimed by the public health community is simply not true.

Second, for individuals aged 25-59 the risks of premature death from being underweight are substantially greater than those of being overweight and they are also slightly greater than those of being obese. For those aged 60-69 the risk of dying from being underweight is much higher than from being even significantly obese, that is with a BMI > 35. Again, the total number of premature deaths due to obesity is 25, 814, while the mortality attributable to being underweight is 37, 746. If anything this points to an epidemic of not fat but thin caused death.

Third, the increased mortality risks from obesity were concentrated in a small sub-section of the population, the morbidly obese (BMI>35), who comprise only 8% of Americans. Yet the obesity hysteria of the public health establishment consistently tells us that 65% of Americans are overweight and headed to an early death.

Fourth even the 25,814 deaths per year from obesity needs to be taken not just with a grain of salt but with enough to keep Chicago's streets ice-free for an entire winter. That's because the results are in many cases not statistically significant, though the authors don't mention this. For example, in the 25-59 year old group the confidence interval for increased risk for the obese with BMI's up to 35 is 0.84-1.72, meaning that we can't be confident that even for this group there is any increased risk of early death. The same is true for those with BMI's up to 30. Moreover, the RR figure -- the Relative Risk for dying from obesity - is, in the authors' words, "in the range of 1-2." This means that there is at the very best a very weak association -- notice, not a causal connection -- between obesity and death. And even this is built on a shaky foundation as the authors note that "Other factors associated with body weight, such as physical activity, body composition, visceral adiposity, physical fitness, or dietary intake, might be responsible for some or all of the apparent associations of weight with mortality." So there it is -- there may in fact be no link between obesity and death. Early deaths might instead be due to diets, body type or lack of physical activity.

All of this raises the question of why the numbers have been so badly wrong. The CDC tells us that this is tricky, technical stuff and estimates are always that -- estimates. Of course the 400,000 deaths per year that has been the foundation of the obesity epidemic was never an estimate -- it was always a "fact". Part of the reason is that the 400,000 number was based, as the authors admit, not on actual weights and heights -- but estimates. And even in those surveys which supposedly used actual weights and heights about 30% of the participants never showed up to be measured.

The real answer, however, is to be found in a companion article also published in JAMA. It notes that despite the fact that Americans have supposedly gotten fatter, the prevalence of high cholesterol level, and high blood pressure -- in short the risk factors for cardiovascular disease -- have declined. Even the prevalence of diabetes, the authors note, remained stable. So given that the prevalence of cardiovascular disease risk factors has declined and the rate of diabetes has stayed stable, it is impossible for so-called obesity-related deaths to increase.

In a world without junk science, results like these would mark the end of the supposed obesity epidemic that is killing us by the thousands. Unfortunately the public health community is already busily discounting the CDC's numbers and telling us that whatever the science says, fat kills. Don't count on it.

The author is a health policy writer living in Canada.


 

Categories:
|

TCS Daily Archives