From The Desk Of Clarence Bass
“The risk of death increased by 20 to 40 percent among overweight persons and two to three times among obese persons.”
~New England Journal of Medicine (August 24, 2006)
I hate to be so blunt, but a new study by scientists at the National Cancer Institute (NCI) warrants an alarmist title--it’s huge and powerful. Those who think being a little overweight is okay are very likely kidding themselves. Few if any question the danger of being obese, but experts have been split on the health risk posed by being moderately overweight—until now.
“A substantial proportion of the U.S. adult population is overweight but not obese,” the NCI researchers noted in their report—which makes the relative risk a big deal. Any association between overweight and mortality has “important clinical and public health implications.”
This debate was fueled last year (2005) when a federally-funded study found a slightly lower death rate for overweight people compared to those of normal weight.
Support for that finding seems to be evaporating in the face of the new study. “The latest studies [a Korean study released the same day reached the same conclusion] contradict controversial research by the federal Centers for Disease Control and Prevention [and other NCI researchers] last year that suggested being a little plump isn’t so bad,” AP Science Writer Alicia Chang wrote the day before the new study was released to the public. “Since then, CDC chief Dr. Julie Gerberding distanced herself from the report and acknowledged potential flaws in the study that included people with health problems who tend to weigh less.” In other words, the normal weight group in the 2005 study was probably skewed by people who were already sick and more likely to die.
Zachary M. Seward, writing in the Wall Street Journal (August 23, 2006), reported essentially the same thing: “After criticism of the 2005 study, the CDC distanced itself from the finding and reiterated its position that excess weight is harmful to one’s health.” Seward added: “Yesterday, the CDC instructed its researchers not to comment on the new study, and a spokeswoman for the agency had no comment as well.” CDC researchers, including those involved in the earlier study, were in effect told to let the new study speak for itself.
The new study, published in the New England Journal of Medicine on August 24, 2006, included more than one half million U.S. men and women (527,265), 50 to 71 years old when they enrolled in the National Institutes of Health-AARP Study in 1995-1996. Mid-life bodyweight was determined by asking participants to recall their weight at age 50. Adding the person’s height allowed the researchers to determine those who were overweight or obese.
Generally speaking, you must be 30 pounds overweight to be considered obese. Using a weight-to-height measurement (BMI), a 5-foot-10 man would be considered overweight between 174 and 208 pounds and obese at 209 or more. Normal weight would be under 174. (Do you need a formula to know where you stand? With a few exceptions, most people probably have a pretty good idea—especially if they take their clothes off and look in the mirror.)
Unlike the 2005 study, this study included a separate analysis controlling for smokers and those with chronic diseases. Unhealthy people and smokers, of course, make it difficult or impossible to isolate the effect of being overweight. Fortunately, the large number of subjects permitted the researchers to effectively use restrictions to “minimize potential bias caused by preexisting disease and smoking.”
In addition, age makes analysis more difficult. “The prevalence of chronic conditions increased markedly with age,” the researchers observed. That’s why they asked participants what they weighed at 50. “We attempted to correct for potential bias from disease-related weight loss by using participants recalled weight at the age of 50 to examine the relation of BMI to the risk of death.”
Smoking is also a complex issue. The risk of death is different for current smokers, former smokers and those who have never smoked. “Restriction of analyses to persons who have never smoked is a powerful tool for addressing this bias,” the report states. Fortunately, the data base included a large number of men and women who had never smoked; and the researchers were able to restrict their analyses to these persons.
These restrictions, of course, lend weight to the conclusions reached. “In our data, the association between overweight or obesity and the risk of death among both men and women were strengthened by the use of these techniques,” states the report. Here’s what they found.
A maximum follow-up of 10 years, through 2005, showed that 61,317 participants (42,173 men and 19,144 women) had died. (The next paragraph may be a little confusing based on what we’ve said so far; just keep reading.)
“Initial analysis showed an increased risk of death for the highest and lowest categories of BMI among both men and women,” the researchers wrote. People in the middle--the overweight--showed no significant increased risk of death--basically the same finding as the 2005 study.
This breakdown, however, included smokers and those who were already ill at the time of enrollment. Again, the large number of participants allowed the researchers to exclude these people without materially affecting statistical significance.
A separate analysis of 186,000 healthy people, who had never smoked, showed that participants who were overweight at the age of 50 were 20 to 40 percent more likely to die prematurely than normal weight people. Participants who were obese at 50 were 2 or 3 times more likely to die. As an interesting aside, the risk of death for underweight participants was substantially reduced when the ill and smokers were excluded.
The study concluded: “Excess body weight during midlife, including overweight, is associated with an increased risk of death.” (Emphasis added)
The Bottom Line
The new study shows again that being overweight “is not a benign condition,” Dr. Frank Hu, an epidemiologist and obesity researcher at Harvard, told AP Science Writer Alicia Chang. (Hu’s study on physical activity, overweight and mortality risk was discussed here several months ago: Fit But Fat Risky, # 142 in our Health & Fitness category.)
Hu continued: “The public health message should be loud and clear. Maintain a healthy weight and preventing weight gain in middle age is important to maintaining longevity.”
Dr. Michael Thun, chief epidemiologist of the American Cancer Society, also talked to Ms. Chang about the new study: “The cumulative evidence is now even stronger” Thun observed. “Being overweight does increase health risks. It’s not simply a cosmetic or social problem.” (Dr. Thun was not involved in the NCI research.)
I’ve said it before and I’ll say it again: Our fate is largely in our own hands.
If you are healthy but overweight, lose the excess weight and keep it off. If you’re overweight and smoke, stop smoking—and lose the excess weight. The chronically ill may not be able to cure themselves, but they can manage the illness to the best of their ability—and they can lose excess weight.
Start now! (You’ll find a plethora of information to help you achieve your goals in the Fat Loss & Weight Control category on this website.)
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