“Just a few extra pounds could mean fewer years, study finds,” headlined a front-page, above-the-fold story in the Washington Post this week.
The study, however, is another pointless exercise in the statistical torture of data that have nothing to confess.
“The 10-year study of more than 500,000 adults found that those who were just moderately overweight in their fifties were 20 percent to 40 percent more likely to die in the next decade,” reported the Post.
It appears to be scary stuff for baby boomers -- the exceedingly health-conscious demographic group targeted by the New England Journal of Medicine study (Aug. 24). But boomers ought not fret over this study.
First, the researchers’ statistical methodology is simply incapable of reliably identifying small increases in risk -- that is those on the order of 20 percent to 40 percent. This fact alone qualifies this study as a prime example of junk science. But you don’t have to take my word for it -- take the word of one of the study’s own sponsors, the National Cancer Institute.
“In studies of disease patterns in human populations, risks of less than 100 percent are considered small and usually difficult to interpret. Such increases may be due to chance, statistical bias or effects of confounding factors that are sometimes not evident,” the National Cancer Institute once stated in an effort to defuse alarm over a study that attempted to link abortion with breast cancer.
The new study is rife with the very problems mentioned by the NCI.
The study data is based on questionnaires collected from 567,169 members of the American Association of Retired Persons (AARP) aged 50-71 living in six U.S. states in 1995-1996.
These data are likely biased to some unknown extent since no effort was made by the researchers to ensure that they aren’t biased. Not only are the data unlikely to be representative of 50-71 year-olds in the U.S., they’re not likely even representative of AARP members since only 18 percent of AARP members completed and returned the questionnaires. Which 18 percent of an already selective demographic? Who knows?
Moreover, none of the data were validated -- not a single study subject’s bodyweight, height, smoking status, physical activity level, alcohol intake or any other key lifestyle or genetic factor that might be relevant to mortality was verified by the researchers. Such “self-reported” data are notoriously unreliable.
The study subjects’ vital status -- that is, whether they are dead or alive -- were obtained from the Social Security Administration’s Death Master File. But the Death Master File doesn’t contain cause of death, so the researchers have no idea what killed any of the study subjects. It could very well be that overweight study subjects killed in automobile accidents or violent crimes are counted by the researchers as being killed by their bodyweight.
The only thing more appalling than the trying to pass off this study as “science” is the shameless effort to prey on the fears of baby boomers.
The editorial accompanying the study, entitled “Overweight and Mortality Among Baby Boomers – Now We’re getting Personal,” written by Dr. Tim Byers of the University of Colorado School of Medicine starts out, “I am a baby boomer and my body-mass index (BMI) is 27.3… Now that studies are beginning to describe the risk of death associated with even modest levels of adiposity among baby boomers, this issue is getting personal for me.”
The researchers, however, didn’t study any baby boomers. The average study subject was born in the early 1930s. The youngest study subject was born in 1945 – a year before the baby boom officially began according to demographers. It’s hardly a study about baby boomers.
More than two years ago, the Centers for Disease Control and Prevention attempted to jump-start panic about bodyweight by claiming that obesity killed 400,000 people per year. Readers of this column knew that figure was junk science more than a year before the CDC was forced to revise it downward more than 90 percent to about 25,000.
Recent studies that have also debunked the notions that low-fat diets make us healthier, dietary fiber reduces cancer risk, dietary salt is unhealthy – to name just a few of the health myths that many of us long ago incorporated into our lifestyles.
Though sound science is steadily shattering myths long-advanced by our health nannies, they apparently think that the way to reestablish their dubious trade is by marketing new fears to whom they seem to perceive as society’s weak link -- aging, health-obsessed boomers.
Maybe their ploy will work -- of course it would help if the nannies actually studied boomers before they scared them.