November 23, 2004
CDC: Obesity Deaths Overstated
"A widely quoted federal study that concluded obesity is poised to overtake tobacco as the leading cause of preventable death inflated the impact of obesity on the annual death toll by tens of thousands due to statistical errors." So reads a front page story in this morning's Wall Street Journal. The Journal's Betsy McKay reports that the Centers for Disease Control and Prevention (CDC) now admits its widely-publicized work was faulty and "expects to downgrade the number of deaths it tied to obesity." The CDC's move comes months after we first discovered and reported that its marquee figure -- popularly reported as 400,000 annual deaths due to obesity -- was deeply flawed.
According to the Journal, a CDC document "concluded that the mathematical errors may have inflated the study's death toll by about 80,000 fatalities, or 20% of the total deaths." The Journal goes on to describe how the CDC's study faced substantial criticism from within the agency itself:
Even before the disputed study was published, several scientists at the CDC expressed misgivings to their superiors about its methodology and findings, according to documents and people familiar with the debate ... "I am worried that the scientific credibility of CDC likely could be damaged by the manner in which this paper and valid, credible, and repeated scientific questions about its methodology have been handled," wrote Terry Pechacek, associate director for science in the CDC 's Office on Smoking and Health, in an April 30 e-mail shortly after the study was published. Dr. Pechacek wrote to colleagues that he had warned two of the paper's authors, as well as another senior scientist, "I would never clear this paper if I had been given the opportunity to provide a formal review."
The Center for Consumer Freedom (CCF) first called attention to the flawed 400,000 deaths figure this summer, when we published a detailed report entitled "An Epidemic Of Obesity Myths." Our subsequent research revealed in September that the CDC study included 80,000 additional deaths because of a simple mathematical error. When pressed about this problem, the study's lead author, Ali Mokdad of the CDC, was most unhelpful. Follow-ups to the original query at one point got this response from Mokdad: "I will be glad to examine the difference and let you know ASAP. Unfortunately, I am all tied up with the flu shortage these days." That was over a month ago.
At the behest of California Congressman Henry Waxman, the Government Accountability Office (GAO) was set to launch its own investigation of the CDC figure at the beginning of 2005. In a report to the GAO earlier this fall, we detailed not only the study's substantial mathematical overestimation, but also its much larger underlying problems.
In the coming days, the Center for Consumer Freedom will be exploring many of the flaws we've documented, a few of which we've reported before. The study, we'll explain, relied on data as old as 1948; failed to account for the crucial reality that obesity doesn't increase death rates among the elderly; inappropriately assumed that all excess deaths among the obese were due to their obesity; and ignored the overwhelming number of studies that find more moderate health risks from obesity.
