Study details how fat costs years

Severely obese adults can lose 5-20 from life depending on sex, race

January 08, 2003|By Jonathan Bor | Jonathan Bor,SUN STAFF

A 20-year-old who is severely obese could lose more than a decade of life to medical complications, according to a new study on a national epidemic that some experts say could rival smoking in its consequences.

Researchers found that the severely obese could lose five to 20 years - depending on whether one is male or female, black or white - and discovered that even a mild paunch can translate into an earlier death.

"The message is that obesity is not a cosmetic problem, not a problem to be made light of," said Dr. David B. Allison of the University of Alabama, Birmingham, who conducted the study with researchers from the Johns Hopkins Bayview Medical Center. "It's a serious condition that can lead to a marked shortening of life span for certain groups."

As public health experts focus increasing attention on the growing problem of obesity, the study gives doctors a concrete way to tell patients what the consequences of their excess weight could be.

Obesity doesn't kill directly but triggers disorders including heart disease, stroke, diabetes and some cancers that can be life-threatening.

Last year, a government study found that two-thirds of adult Americans were overweight or obese, up from a quarter in the 1960s. Nearly 16 percent of teen-agers were overweight, according to the National Center for Health Statistics.

Dr. Kevin R. Fontaine, a Bayview rheumatologist who was the study's lead author, said the findings do not necessarily mean that adults who lose weight can win back the years they might have lost. Further studies will have to settle that, he said, although doctors know that weight loss improves a person's overall health outlook.

"We certainly know that if you are obese and lose weight, you reduce blood pressure and cholesterol, reduce the risk of type-2 diabetes and certain cancers," Fontaine said.

The study, published in today's Journal of the American Medical Association, used data from more than 14,000 adults compiled in a national health survey to calculate the life spans of people of varying girth.

For the comparisons, the authors used body mass index - a number that takes into account a person's height and weight.

Most startling were the years of life lost among the severely obese. Researchers highlighted the effect on adults whose body mass index was greater than 45. Examples include someone who is 6 feet tall and weighs at least 332 pounds and someone who is 5-feet-4 and weighs 233 pounds.

For a 20-year-old white man, this means losing 13 years of life. Rather than living to 78, the average for a man, he would live to 65. The average white woman would lose eight years, living to 73 rather than 81.

Black men in this group lost the most, an average of 20 years. Black women lost the least - an average of five years.

The authors could offer no reasons for the racial disparities, saying they limited their study to statistical comparisons. Just as perplexing was the fact that mildly overweight black men and women appeared not to sacrifice any years.

Among black men, weight did not seem to affect longevity until they reached moderate levels of obesity - for instance, 6 feet and 258 pounds. Then, increased girth exacted a rising toll. Among black women, the effect showed up only among those who were severely obese.

Among white men and women, being mildly obese meant losing a few years of life.

For instance, a 20-year-old white man with a body mass index of 30 (say, 6 feet and 228 pounds) loses an average of two years. A white woman with the same body mass index (say, 5-feet-4 and 180 pounds) loses an average of a year.

Allison cautioned not to make too much of the differences between blacks and whites. It is possible that the statistics for blacks are skewed because they are more likely than whites to die earlier of other illnesses.

Further research, he said, is needed to determine whether the way fat is distributed in a person's body affects life span. The toll might be different depending on whether fat tends to be concentrated beneath the skin, in the abdomen or muscle.

In an editorial also appearing in JAMA, Dr. JoAnn E. Manson and Shari S. Bussuk of Boston's Brigham and Women's Hospital said the study provides a useful way to measure obesity's toll.

But it is not the total picture, they wrote. Obesity also compromises a person's quality of life by increasing the risk of arthritis and non-fatal diabetes and heart disease.

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