Wednesday, November 24, 2004 - Page updated at 12:00 AM

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Obesity deaths inflated by math error

The Associated Press

ATLANTA — A widely reported government study that said obesity is about to overtake smoking as the No. 1 cause of death in the United States contained mathematical errors and may have overstated the problem, health officials acknowledged yesterday.

The government is working on a rare correction to the study.

The Centers for Disease Control and Prevention said in March in a study co-authored by its director, Dr. Julie Gerberding, that poor diet and physical inactivity were responsible for 400,000 deaths in 2000, a 33 percent jump from 1990.

However, the CDC acknowledged yesterday that it made an error in calculating how many people died because of obesity in the past decade. CDC officials said they are still determining the correct number of deaths.

The Wall Street Journal reported that the agency may have overstated the figure by 80,000, representing an increase of less than 10 percent from 1990 to 2000.

The CDC has corrected articles in major journals before, but "unfortunately it was a paper that received a lot of attention and had our director's name on it. To my knowledge that confluence of events really hasn't occurred at the same time," said Dr. Dixie Snider, the CDC's chief of science, who was appointed to lead the agency's investigation of the error.

The mistakes consisted of simple mathematical errors, such as including total deaths from the wrong year, the newspaper reported.

"Eighty-thousand is an estimate from one of our scientists — that's not a number we're going with," said Snider, who declined to speculate on the correct number of obesity-related deaths.

The CDC plans to submit a correction to the Journal of the American Medical Association, which published the study in March. The correction will explain how the error was made, said CDC spokesman Tom Skinner.

The agency also has asked the Institute of Medicine, a federal scientific advisory organization, to hold a two-day workshop next month in Washington to reach a consensus on the proper way to calculate the health effects of obesity. That is because the study also caused disagreement in scientific circles over how deaths can be labeled obesity-related.

In addition, the agency is reviewing how to prevent "miscommunication" among scientists when subjecting studies to expert review before they are published.

The errors apparently were discovered soon after the CDC study was published, as scientists inside and outside the agency began to dispute its findings, publishing letters in JAMA and the journal Science.

That prompted the CDC to begin an internal review. Rep. Henry Waxman, D-Calif., also asked the General Accounting Office, the auditing arm of Congress, to investigate.

The agency originally announced that more Americans could soon be dying of obesity instead of smoking if current trends persisted. It put the number of obesity deaths at 400,000, compared with 435,000 from tobacco.

But even when the errors are corrected, Skinner said, "it's not going to change the fact that obesity is the second leading cause of preventable death."

In other health news:

New MS drug: The Food and Drug Administration yesterday approved a drug that tries a new method of attacking multiple sclerosis, an incurable disease of the central nervous system that affects 350,000 Americans.

Earlier this month, the makers of natalizumab — which will be sold under the brand name Tysabri — reported that 942 MS patients who took the drug for one year had a 66 percent reduction in relapses, compared with those who took a placebo. That compares with a 30 to 35 percent reduction in relapses for products currently on the market.

Accutane controls: Doctors who prescribe the acne drug Accutane and its generic equivalents, pharmacists who dispense it and patients who take it will be registered in a central database under toughened government rules for a drug linked to birth defects. Women of childbearing age also will need to provide documentation of a negative pregnancy test before getting the drug, known chemically as isotretinoin. Previous safeguards on the drug were mostly voluntary.

The FDA's move came in response to a whistle-blower's concern that Accutane and four other drugs remained on the market despite safety concerns.

Copyright © 2004 The Seattle Times Company


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