The careful reader will know that I’m no fan of epidemiological studies. I expect that they have their uses in some arenas, but the context in which I tend to see them is personal health — and they’re generally worse than useless. But even worse than a run-of-the-mill epidemiological study is one based entirely upon self-reported data.
“Hi, I’m calling from the Center for Disease Control and Prevention. I’d like to ask you some questions about your loathsome, immoral, un-American fatassedness. To begin, what is your current height and weight?”
Does that sound like a reliable method for obtaining high-quality data to you?
Hence, I find this report utterly hilarious:
Looking at the numbers shows the wide discrepancy between what people say on the telephone and the physical evidence of actually getting weighed. When weighed in the REGARDS study, all of the regions’ obesity’s numbers went up — it’s just that the southern region numbers went up less.
“Everybody underreports their weight but women do it more,” Howard said.
Men, on the other hand, do something else that affects the Body Mass Index, which is weight divided by height squared and is used to define obesity.
“They overreport their height, which makes them seem less obese.”
It’s difficult to tell from the abstract whether the authors somehow corrected for the BMI’s manifold and obvious deficiencies, but it hardly matters. The real punchline here is that many published obesity researchers — and the policy wonks who craft legislation from their abstracts and maybe a few of the more colourful figures — are astonishingly naive.