Wednesday 2 January 2013

BBC expresses scepticism about study!

There are two ways to report news that divides opinion. The first is to report what has happened and then include comments from those who have a view on it, including critics. The second is to lead off with disparaging comments from the critics so that the news itself becomes incidental. This latter approach amounts to poisoning the well and is mainly favoured by propagandists and media outlets which have a blatant editorial bias. So, with that in mind...

From the BBC:

'Weight is healthy' study criticised

A study which suggests being overweight can lead to a longer life has caused controversy among obesity experts.

One labelled the findings a "pile of rubbish" while another said it was a "horrific message" to put out.


The study in the cross-hairs is a meta-analysis published in the Journal of the American Medical Association which assessed 97 individual studies encompassing a total sample group of 2.88 million people. Not the kind of paper the Beeb would normally be sniffy about, but the meta-analysis found that the overweight and mildly obese people had a lower mortality rate than those of 'normal' weight.

The results for overweight people (BMI of 25-30) were statistically significant (RR = 0.94 (0.91-0.96)) while the results for mildly obese people (BMI of 30-35) were not (RR = 0.95 (0.88-1.01)). I am hesitant to take either of these results as conclusive proof that carrying a bit of timber extends your life, but it seems to me sufficient evidence that it does not shorten it.

Although the findings have been described as "counterintuitive", they really aren't. BMI is an extremely simplistic, nineteenth century measurement and the claim that those with a BMI of 25+ are "overweight" is entirely arbitrary. Moreover, as The Science Bit points out, this is hardly the first time such findings have been recorded.

But they drive 'public health' campaigners wild...

Prof John Wass, vice-president of the [Royal College of Physicians], said: "Have you ever seen a 100-year-old human being who is overweight? The answer is you probably haven't."

So much for systematic reviews and sober science! Are these really the words of a medical man or did the BBC ask a bloke in a pub for his 'folk wisdom'? I thought public health people had rejected any discussion of centenarians after it was shown that they don't generally lead healthy lives?

Wass continues:

"Huge pieces of evidence go against this, countless other studies point in the other direction."

Some do, some don't. That's the nature of epidemiology, hence the need for systematic reviews to assess the weight of evidence, and the weight of evidence points towards a null or protective effect from overweight and mild obesity. I repeat—this is not a single study; it is a review of 97 different studies conducted all around the world over several decades. There are not "countless" studies, let alone countless studies which "point in the other direction". There are dozens of studies which have been counted and, taken together, they indicate that mildly overweight people live longer than the lean.

Other experts criticised the research methods.

Alas, the BBC does not feel the need to bore us with the details of these substantive criticisms and so instead we get a variation of the 'sick quitter hypothesis'.

"Some portion of those thin people are actually sick, and sick people tend to die sooner," according to Donald Berry, from the University of Texas

This is true. As with all epidemiology, causation cannot be proven. Some of the thin people will indeed be sick. But, if being overweight is as unhealthy as the nanny statists claim, some—nay, many—of the fat people will also be sick and therefore be likely to die sooner. The fact that, as a group, they actually die later is a hole in the theory that cannot be blithely dismissed with reference to a single, unquantified and unproven confounding factor. Moreover, the authors address this question and note that "most studies" find that pre-existing disease is not an "important source of bias" and that those which control for this factor found that it had "little or no effect".

Lame as they are, the criticisms above are positively high-minded compared to those which follow.

Dr Walter Willett, from the Harvard School of Public Health said: "This is an even greater pile of rubbish" than a study conducted by the same group in 2005.

Willett made his point even more strongly when speaking on NPR yesterday...

"This study is really a pile of rubbish and no one should waste their time reading it."

How heartening it is to see the spirit of intellectual enquiry thriving at the Harvard School of Public Health. Perhaps Dr Willett and his friends will make a bonfire out of copies of the Journal of the American Medical Association and dance around it.

Tam Fry, from the National Obesity Forum in the UK, said: "It's a horrific message to put out at this particular time.

For God's sake man, it's a meta-analysis in a scientific journal released at the start of the year, not the director's cut of The Innocence of Muslims released at the start of Ramadan.

"We shouldn't take it for granted that we can cancel the gym, that we can eat ourselves to death with black forest gateaux."

This hysterical misrepresentation of the study's conclusion is the final line of the BBC's report. In total, the Beeb quoted four people who hated the study's findings but were apparently unable to explain what was wrong with them. The Beeb did not bother to include any quotes from supporters of the study, nor—and this is highly unusual—from its authors.

Perhaps the BBC's health editor has made a new year's resolution to treat epidemiological studies with cynicism and contempt. That would be most refreshing given their past output, but I suspect the scepticism will be extremely short-lived.


Ivan D said...

The BBC bosses do seem determined to destroy what little remaining credibility the corporation has for quality news. Why else would they give the health editor's job to someone so incompetent, uncritical and agenda driven?

Christopher Snowdon said...

I notice the reporters have stopped putting their name to BBC health stories. Shame? Guilt? Thinking about their future careers?

nisakiman said...

It does seem to be the meme for our current era - if the orthodoxy doesn't fit the facts, then make the facts fit the orthodoxy. We see this approach in all the major issues now, most notably "health" and climate change.

There must surely come a point when the serious scientists say "enough is enough" and break ranks. We can't continue deluding ourselves indefinitely. It's just too expensive, both financially and socially.

Sobers said...

I'm not sure as to what this study is saying - have 2.8m people been studied for their entire lives, their weight been assessed on an ongoing basis, and then their mortality rates compared with their average weights?

Or is it just 'this person has died and is fat now' vs 'this person has died and is thin now'?

Because if its the latter, by definition, lots of people get thin before they die - cancer victims for example. So comparing age at death with weight at death doesn't help much IMO.

Séan Billings said...

Wow, this is the exact same argument that happens when you point out that, statistically, moderate drinkers live longer than teetotallers. The health police love meta reports as long as they say what they want them to say, but have a problem with the method when an inconvenient truth bubbles to the surface.

Jonathan Bagley said...

"Have you ever seen a 100-year-old human being who is overweight? The answer is you probably haven't."

Probably because everyone becomes thin when they are old.

Fredrik Eich said...

"Obese face 'exercise or lose benefits' threat, council says"

Furor Teutonicus said...

XX "Have you ever seen a 100-year-old human being who is overweight? The answer is you probably haven't." XX

No...not that I know of, but then in all my years visiting, hospitals, and now working in one (having "retired" from my previous job), I have VERY rarely seen any one "overweight" in the heart-attack wards either.

And WHEN was the last time one of these REALLY fat bastards was in the news for anything more serious than stealing our tax money to eat, or that the fire brigade had to order a low loader to get them to their toe nail polishing studio?

Ever heard of one dying of a heart attack?

Anonymous said...

Snowdon said...

I notice the reporters have stopped putting their name to BBC health stories. Shame? Guilt? Thinking about their future careers?

It seems the recruitment of researchers for anti-tobacco and anti-obesity studies is getting harder and harder as the Nannys try and gather all the new Grads they can to put their names upon more junk science to keep the spin machine running.......I gather the older more experienced lot have figured it out and dont want to be shamed later on as indeed these reporters you talk about dont either.

Anonymous said...

UCSF recruiting our next class of postdoctoral fellows
Submitted by sglantz on Thu, 2013-01-03 14:30

Academic Background Required:Doctorate/Equivalent Degree

The purpose of the fellowship is to attract individuals from a wide variety of backgrounds in medical, biological, social, behavioral, and policy sciences to develop a new generation of academic leaders in tobacco control. Upon completion of training, fellows will be well positioned to be active participants in crucial policy debates about the future development and implementation of tobacco control interventions.

Colonel Shotover said...

Happy new year Chris, look forward to reading your blog through 2013.