Friday, 24 May 2013

Science versus public health

Back in January, I wrote about the research that shows that being overweight does not increase mortality risk and may reduce it. This has been shown many times and a large meta-analysis of 97 studies, put together by Katherine Flegal et al. and published in JAMA, appeared to confirmed it.

Cue panic from the public health lobby who feared that the 'obesity epidemic' and all its limitless possibilities for social engineering were in jeoprady. In an astonishing outburst against a fellow academic, the longtime foe of 'Big Food', Dr Walter Willett, said:

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

As I said at the time...

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.

Willett and friends did not quite build a bonfire but, as Nature reports this week, they did go to the effort of organising a kangaroo court at which Flegal was tried for her crimes against public health hysteria.

Willett later organized the Harvard symposium—where speakers lined up to critique Flegal's study—to counteract that coverage and highlight what he and his colleagues saw as problems with the paper.

The problem for the Willetts of the world is that Flegal's study was pretty sound and a growing number of non-fanatical scientists are coming to accept that being overweight is not a serious health problem. There are potential confounders, including the fact that smokers tend to weigh less than nonsmokers, but—as with the 'sick quitter hypothesis' and alcohol consumption—the theory has stood up to every challenge and remains robust.

More and more studies show that being overweight does not always shorten life — but some public-health researchers would rather not talk about them.

...the most contentious part of the debate is not about the science per se, but how to talk about it. Public-health experts, including Willett, have spent decades emphasizing the risks of carrying excess weight.

Studies such as Flegal's are dangerous, Willett says, because they could confuse the public and doctors, and undermine public policies to curb rising obesity rates.

“There is going to be some percentage of physicians who will not counsel an overweight patient because of this,” he says. Worse, he says, these findings can be hijacked by powerful special-interest groups, such as the soft-drink and food lobbies, to influence policy-makers.

Just take that in for a moment. What kind of scientist talks like this? The truth will undermine our political activity! The food industry will use scientific facts to oppose us! Too bad, Walter. Policy is supposed to be based on the facts, remember?

But many scientists say that they are uncomfortable with the idea of hiding or dismissing data — especially findings that have been replicated in many studies — for the sake of a simpler message.

That's reassuring, up to a point. It's kind of worrying that a scientific journal needs to point that out to its readers, but that's what thirty years of 'public health' research has done to science. And I'd be more reassured if it said "most scientists" rather than "many scientists".

Willett says that he is also concerned that obesity-paradox studies could undermine people's trust in science. “You hear it so often, people say: 'I read something one month and then a couple of months later I hear the opposite. Scientists just can't get it right',” he says.

Once again, too bad. Zealots decide what to believe early in life and then stick to it regardless of the facts. Scientists don't (or, as Nature says, "many scientists" don't). As Keynes said, when the facts change, I change my mind. Are we supposed to seal the scientific consensus of 1990 in concrete just so you could fight your childish battle with the soda industry?

“We see that time and time again being exploited, by the soda industry, in the case of obesity, or by the oil industry, in the case of global warming.”


Be under no illusions about what these people are up to. They are prepared to defame academics and misrepresent data in a conscious bid to mislead politicians and manipulate the public. They are not just prepared to do this, they have already done so.

This is the problem with mixing science and politics and it is endemic in the sordid oxymoron of 'public health'. Science wants to inform. Public health wants to manipulate, control and socially engineer. The two aims are incompatible. Public healthists believe they are fighting a war, and truth is always the first casualty.

I recommend reading the Nature article in full as well as the accompanying editorial. It gives an insight into how laughable is the idea of evidence-based public health policy.

1 comment:

Rob Lyons said...

Had exactly the same thing on Five Live the other day. Craig Currie - the researcher behind the 'lazy porkers' comments about type-2 diabetics - agreed with me that there was little difference in risk between normal, overweight and mildly obese people, but that it was a 'dangerous argument' nonetheless.