French Scientists Link Higher BMI with Lower IQ 728
Xemu writes "French scientists have linked obesity to lower IQ reports the Telegraph. In a new five-year study of more than 2,200 adults, people with a low body mass index (BMI) could recall 30% more words in a vocabulary test than those who were obese. The fatter subjects also showed a higher rate of cognitive decline when they were retested five years later. In the United States, 30% of the population is obese according to OECD. That's the highest rate of obesity anywhere. Do these high obesity rates affect the average IQ of the population?" (Of course, this sidesteps discussion of whether IQ tests measure anything significant at all.)
IQ Tests (Score:5, Informative)
This wasn't a general purpose IQ test. It was a specific test of people's ability to recall words. They're talking about memory in particular, not some fuzzy idea of general intelligence.
Re:BMI is not accurate (Score:2, Informative)
Re:The average IQ? (Score:1, Informative)
Therefore by definition the average IQ cannot change. If everyone suddenly got a lot smarter, the average IQ would be the same as it is now: exactly 100.
Re:How can this be true... (Score:2, Informative)
Poor translation (Score:1, Informative)
Hmmm, you may have a point; (Score:1, Informative)
Yup, I think you might just be on to something there.
Memory != IQ (Score:5, Informative)
This is simply not true. If you actually take an IQ test, you will see that it does not test your memory as had been done in the study, but rather your cognitive thinking skills. In fact, there are many people who can memorize history or math equations or whatever, but they come up far short when they have to apply the concepts they memorized.
Again, memorization is not critical thinking, and memorization != IQ.
A truly groan-worthy pun... (Score:4, Informative)
Re:BMI is a poor way to measure body fat. (Score:5, Informative)
All the BMI measures is your risk for a variety of heart related ailments. The theory is that the more massive you are, the harder your heart has to work.
The issue is most people lack the ability, the financial resources, and the discipline to gain an extraordinary amount of muscle mass. So, in the vast majority of cases, the BMI does measure body fat. But, it has nothing to do with the percentage of your body that is fat or how toned you are.
Just thought I would add that to what you are saying.
Re:Mutual Admiration (Score:3, Informative)
friendly and attractive (and ideally drunk) women
anyone who wants to play MarioKart with me
funny people
foreigners (cultural comparisons are interesting)
People who accomplish things are generally tedious and self-important. Witty losers are where it's at.
Superficial analysis of actual article, plus link (Score:3, Informative)
Now, some comments. The idea that correlation doesn't imply causation is correct, but this paper used a multivariate analysis to attempt to control for several possible confounding factors. I count twelve that the authors thought about and included in some of their models: age, sex, educational level, diabetes, systolic blood pressure, daily alcohol intake, physical activity, perceived health score, perceived stress score, energy, social isolation, and region of residence. It looks like the paper acknowledges more confounders than anyone's mentioned here on Slashdot so far. Ultimately, though, this paper is a cohort study, so you can still argue that they missed a confounding factor. If you can think of a legitimate one, you stand a good chance getting it published in the journal Neurology.
Next, naming intelligent friends with high BMIs or famous thin people with questionable smarts does not change what this paper says, of course. Let's even pretend to add those people to the data. Now we have 2243 subjects instead of 2223. I doubt that changes the results much, but I admit I can't prove that. Counterexamples do tell us something very important, though. If high BMI really causes worse word-list learning, it is still one of a staggering number of other effects on this measure, and it by no means excludes anyone from higher intelligence.
Lastly, people are right to wonder what cognitive tests like word-list learning really measure. This paper didn't use IQ directly, but the point still stands. The authors know this and address it, too. "The functional significance of cognitive changes in our sample is difficult to assess.... We did not collect any direct index of work performance." In fact, they don't know whether differences in these psychometric test scores apply to "this healthy working population." BMI, too, may represent a surrogate marker. The association in this paper still stands, although I don't see anything about whether active weight loss attempts change cognitive point measures or decline. Yes, there are other markers of cardiovascular risk, and these include waist circumference (Am J Cardiol 2006;98:1053-1056), which someone could study in the same way that the Neurology paper studies BMI.
So what's the point? The point is, the differences in these cognitive tests concern some people. The results suggest that some real effect on cognition exists, and the authors mention a few reasonable mechanisms for the effect. If you agree that a normal BMI leads successively to less diabetes, less coronary artery disease, and less chest pain when you walk around, then it makes sense to try for a normal BMI if it's even possible that it will save blood vessels in your brain, or your brain cells directly, or whatever mechanism you believe. It wouldn't surprise me, though, if weight loss merely slows cognitive decline or lessens the risk, rather than positively improving intelligence or some similar claim. The other point is that newspapers check sources and strive to do it very well, but they rarely offer substantial analysis of original research. They will quote authorities regarding the research but leave item-by-item discussion to commentary articles in specialty journals. Even my couple hundred words here only begin to address the reasonable analysis of this or any scholarly article.
Re:Link with poverty (Score:2, Informative)
Now we have excess refined food, sugar, etc. Being properly fit these days is a sound indication of financial status, as you need time to workout (time == money), and some money to get into a gym or something alike (except, of course, if you are Rocky Balboa: stairs work just fine for him), and a decent diet (which also became expensive, if you eat out).
Poor people were condemned to a life of famine and generalised lack of nutrients these days and now, on most post-industrialised societies, they are condemned to a life of high cholesterol, diabetes, and a generalised lack of nutrients!
Re:BS on both counts (Score:3, Informative)
Not at all. Doctors and nurses use charts; most people use charts or web calculators like this one [nhlbisupport.com].
Mostly "quick and dirty" applies to medical research, where it's quick, cheap, and routine to record a patient's height and weight. You don't need extra funding or specially trained staff to measure height and weight consistently, and in many cases, that data is already recorded as a matter of course. It's an easy statistic to use in a study or to apply retroactively to existing data. The extra complexity of dealing with inches and pounds doesn't matter, since the data is handled in bulk by software.
study doesn't say anything about "obese" people (Score:4, Informative)
In particular, they broke up BMI's into five groups: (1) 15-21.5, (2) 21.5-23.4, (3) 23.4-25.2, (4) 25.2-27.7, and (5) 27.7-45, where BMI's up to 25 are considered normal, up to 30 are considered overweight, and over 30 are considered obese. Even within the final group, not all the participants are obese.
It begs the question of why they didn't compare "normal" weight IQ's to "obese" weight IQ's, as this would be a big story and a more impressive research finding! It's likely that either they didn't have enough obese participants to satisfy statistical significance (so most of group (5) is actually individuals with BMI's of 27.7 to 30), or they didn't find that obese people had lower IQ's. When the BMI groups that they break up their data into as strange as this, and not at all the groups that are normally used in research papers, it begs the question of what kind of data massaging they had to do to find their conclusions. Did they try 100 different breakdowns of BMI groupings until they found one that (barely) satisfied statistical significance?
I remain skeptical as to the conclusions of this paper.
Re:A truly groan-worthy pun... (Score:2, Informative)
Re:BMI is not accurate (Score:3, Informative)
Wow, eh, do you do steroids or something ?
Muscle mass gain is usually measured in X * (100 grams) per month, if you're working out once in a while. Only by working out almost constantly you can build up a kilogram of muscle mass per month, but that's hard, painful work. You're certainly not building up 16 kg of muscle mass in one year, unless you have some sort of genetic mutation or do steroids.