Monday, 21 June 2021

The hounding of Katherine Flegal

Way back in 2013, I wrote about 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. It found that people who are overweight have a slightly reduced risk of mortality compared to people of 'healthy' weight (RR = 0.94 (0.91-0.96)).

I first wrote about it when it was published because the BBC was using the old trick of putting criticism of the study front and centre. 

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 criticism from certain people was fierce. So fierce as to suggest a religious schism rather than a scientific debate. Tam Fry, from the National Obesity Forum, said: 
"It's a horrific message to put out at this particular time. We shouldn't take it for granted that we can cancel the gym, that we can eat ourselves to death with black forest gateaux." 
That was a bit of a straw man, but it was constructive and courteous compared to the quote from veteran anti-obesity crusader Walter Willett of Harvard School of Public Health:

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

And that is pretty much what he did. As Nature subsequently reported, Willett "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 study's lead author, Katherine Flegal, has now written a full account of what happened and it really shows what you leave yourself open to when you get on the wrong side of 'public health' activists. The data she had was fine and her findings have been replicated many times. Her critics' problem was not really with the data but with 'the message' her findings supposedly sent out. This was obvious from Tam Fry's comment above as well as subsequent comments made by Walter Willet, such as...

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.
... 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.
“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.”

And so she was attacked and hounded. It turns out that this process had been going on since 2005 when, as a scientist at the CDC, she published a study which...
...found that overweight was associated with slightly but significantly fewer deaths than normal weight. A quick glance at the literature suggested that our findings about overweight were not particularly unusual. We were unprepared for the firestorm that followed.

You should read the whole article (no paywall), but here are a few lowlights from her experience:

I fielded dozens of press calls as soon as our article was published. To my surprise, after the first few hours, many of the journalists who called me had already spoken to a professor, Walter Willett, (let's call him Professor 1) from a prestigious school of public health (PSPH). He was not a statistician and had no expertise in estimating the number of deaths associated with obesity. Our article was not intended to have anything to do with his work. He had apparently begun pre-emptively contacting the press, inserting himself into the discussion, positioning himself as an expert, and providing negative and antagonistic comments on our article before reporters had spoken to me. He used strong language to disparage our article, describing it as “really naive, deeply flawed and seriously misleading”.

.. In the same year, a post-doc at PSPH posted the following on a blog: “Numbers from Flegal's paper had been subsequently RETRACTED [sic] by the CDC, and she has subsequently been demoted at the CDC for writing the erroneous paper.” Every single one of these statements was false. CDC had not retracted our findings, and I had not been demoted. In fact, our paper had received CDC's highest science award, the Shepard award, in 2006.

.. Around the same time, some unusual statements were anonymously inserted in the Wikipedia entry on “overweight.” These statements asserted with no references that our article had been “widely discredited and regarded as fatally flawed by researchers from the Harvard School of Public Health, Harvard Medical School, American Cancer Society, and even the CDC agency itself, which has backtracked on the findings from the Flegal report.” This was part of what appeared to be an ongoing campaign to present our article incorrectly as having been repudiated by reputable sources.

.. In 2007, I accepted an invitation to give a named lecture at the 2008 meeting of a scientific society. The invitation included no mention of a rebuttal. When I received the final program a month before the meeting, to my surprise Professor 2 from PSPH had been added as a rebuttal speaker. This is an unusual way to treat an invited lecturer. As part of Professor 2's rebuttal, he presented a slide supposedly “based on” our research that strangely showed precisely the opposite of what we had found. It turned out that Professor 2 and his group had misunderstood a table in our published article and misinterpreted the results. Although I wrote him an email to clarify the table, Professor 2 and his colleagues nonetheless submitted an article for publication with the same errone- ous analysis. Fortunately, their article was rejected. This led me to realize that if such an article were to get published with such an erroneous analysis, it would likely be quite difficult for me to ever correct the situation. This episode as well as others also led me to realize that some, perhaps many, of our critics had very little understanding of our article.

.. Another line of attack was something like “this is just one study.” According to the 2007 hit piece in Scientific American, “Decades of re- search and thousands of studies have suggested precisely the opposite ...”, adding “Flegal is not necessarily wrong, but the preponderance of evidence clearly points in the other direction.” In fact, many other studies had already shown no excess mortality associated with overweight. The 2013 obesity guidelines put out jointly by the American Heart Association, the American College of Cardiology and The Obesity Society, also reported the finding that overweight did not appear to be associated with excess mortality, rating the strength of the evidence as “moderate.” Professor 2 was a coauthor of these guidelines. 

The initial intent of these attacks seemed to be to discredit our work completely. They employed denigrating and insulting remarks (“rubbish,” “ludicrous,” “complete nonsense,” “fatally flawed and widely discredited”) implying that our work was not worthy of serious consideration. There were also suggestions that we were unqualified, and my integrity and competence were questioned. Some attacks were surprisingly petty. At one point, Professor 1 posted in a discussion group regarding salt intake that JAMA had shown a track record of poor editorial judgment by publishing “Kathy Flegal's terrible analyses” on overweight and mortality. Similarly, again using a diminutive form of my name, Professor 1 told one reporter: “Kathy Flegal just doesn't get it”. It became clear that one of the things that critics found disturbing was that what they called the “lay media” or the “popular press” (which apparently extended to the New York Times, Scientific American and even Nature, a leading scientific journal) had reported on our findings as though they were worthy of serious discussion. One of the effects of the public insults may also have been to deter or intimidate other investigators. An anonymous researcher was quoted elsewhere as saying if character assassination is the price for publishing data that contradicts established beliefs, fewer academics will be willing to stick out their necks and offer up fresh thinking.

This is the 'public health' playbook. When the evidence doesn't go your way, resort to appealing to authority (as Flegal says, Willett is a leading academic in nutrition but not in the kind of work she does). Resort to the media (the BBC was only too happy to slant its coverage in their direction). Resort to editing Wikipedia, to holding one-sided symposiums, to fiddling the figures and to personal abuse. 
We've seen it before with the Australian sugar 'paradox' and very recently with vaping. Even John Snow got this treatment when he contradicted miasma theory. As far I can tell, the only part of the playbook that was not employed in this instance was accusing Flegal of being funded by 'Big Food', but I bet they were tempted. 

It's an incredible amount of defensiveness for an issue that shouldn't really matter. It's not an 'obesity-paradox' because people who are overweight are not obese. It should be possible to accept that people who exceed the entirely arbitrary BMI threshold of 25 - but who are not obese - do not suffer significant health risks, while those who exceed the threshold of 30 do - and that the fatter they get thereafter, the greater the risk.

But 'public health' doesn't really do nuance, does it?

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