Study Tying Longer Life to Extra Pounds Draws Fire

Even scientists have difficulty when their theories are challenged. The establishment does not like this article. I first commented on the original article in April – Maybe we should have a small spare tire. I also found an amusing commentary – Amusing commentary on the overweight is good article.

This group is not amused.

The study under attack was published last month by researchers at the Centers for Disease Control and Prevention and the National Cancer Institute. It concluded that people who are overweight but not obese have a lower death risk than people of normal weight. The scientists also reported that being very thin increased the risk of death, even if the thinness was longstanding and not due to illness.

In a seminar and news conference yesterday at the public health school, in Boston, the critics said other studies, including their own, had found that the death risk from excess pounds increased continuously from normal weight to overweight to obesity.

Dr. Scott M. Grundy, a heart researcher at the University of Texas Southwestern Medical Center, said excess weight clearly led to heart disease and death. Dr. Michael Thune of the American Cancer Society said the same applied to cancer.

Other criticism came from Dr. Frank Hu, an associate professor of nutrition and epidemiology at Harvard. Dr. Hu, citing the Nurses’ Health Study, which enrolled 120,331 women in 1976 and followed them, noted that as body mass index increases, “the death rate increases dramatically.”

He and a colleague, Dr. JoAnn Manson, said the federal analysis had failed to exclude smokers and people who were already ill. “That can lead to serious underestimates of mortality linked to overweight and obesity,” Dr. Manson said.

Dr. Walter Willett, chairman of the department of nutrition at the public health school, agreed, calling the analysis “deeply flawed.”

But Dr. Katherine Flegal of the disease control centers, the lead author of the contested paper, said she and her colleagues had analyzed their data in a variety of ways. They looked at the results both with and without current or former smokers and people who had chronic diseases, Dr. Flegal said. The results always came out the same, she said: there was no mortality risk from being overweight and little from being obese, except for the extremely obese.

One of her co-authors, Dr. David F. Williamson of the centers, said one reason for the discrepancy between their results and other findings might be the populations under study. The Harvard group looked at nurses, and the cancer society looked at volunteers. “We have data sets that are truly nationally representative of the U.S. population,” Dr. Williamson said.

Epidemiologic studies are wonderful, yet dangerous. We must always extrapolate epidemiologic findings with great care.

So here we have a dispute amongst epidemiologists, each claiming that they have better data. Perhaps we will never know the answer to the fundamental question – what is ideal weight? I hope the latest study which allows for being mildly overweight is actually correct. Clearly, we have two strong opinions, both backed by data. I doubt that we can sort this one out easily.

Related posts:

1. Overweight and obesity linked to heart failure
2. Maybe we should have a small spare tire
3. On obesity and overweight – observations from Paris
4. Amusing commentary on the overweight is good article
5. Evidence for a healthy lifestyle

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