Jun 01, 2013 3:33 PM GMT
In an extraordinary editorial and feature article, Natureone of the world’s pre-eminent scientific journals, has effectively admonished the chair of the Harvard School of Public Health’s nutrition department, Walter Willett, for promoting over-simplification of scientific results in the name of public health and engaging in unseemly behavior towards those who venture conclusions that differ to his.
Willett, who is one of the most frequently quoted academic sources on nutrition in the news media, appears to have crossed a Rubicon when he denounced Katherine Flegal, an epidemiologist at the US National Center for Health Statistics, for publishing a study that showed people who were overweight (but not obese) lived longer than those deemed normal weight. “This study is really a pile of rubbish, and no one should waste their time reading it,” he told National Public Radio.
Flegal had derived this conclusion from a meta-analysis of 97 studies covering 2.88 million people, and it had been published in the prestigious Journal of the American Medical Association (JAMA). What concerned Willett – and other public health experts, who as Nature reported, later staged a symposium to criticize it – was that it seemed to counteract the general message that people should lose weight. As the journal noted:
“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 is well know for being forthright in his views; but describing Flegal’s work as a “pile of rubbish” appears to have ticked off obesity researchers and biostatisticians alike, for this isn’t the first study to arrive at such a finding – and researchers lined up to tell Nature why it was plausible: a little extra weight for those who were older or older and ill, could help rather than hurt. Moreover, Flegal herself responded with some sharp statistical criticism of Willett’s “rubbish” thesis.
There was also a spectacular irony in Willett’s complaints about Flegal’s study that will not have gone unnoticed in scientific circles, namely that Willett was the co-author of a study published last fall that generated enormous controversy when its dramatic conclusions were retracted at the last minute by the publicity team at Harvard’s teaching hospital, Brigham and Women’s. The study had been promoted to the media as showing a link between aspartame and cancer: “The truth isn’t sweet when it comes to artificial sweeteners,” said the press release. But the truth was that the statistical findings were so weak and confusing that no such claim could be supported, especially given that many systematic reviews of the evidence on aspartame had not found any such link.