Obesity Cuts Life Span for Young Adults
By LINDSEY TANNER
AP Medical Writer
January 7, 2003, 4:17 PM EST
CHICAGO -- Being obese at age 20 can cut up to 20 years off a person's
life, with the biggest impact on black men, according to yet another
study that underscores the long-term dangers of being overweight.
The research appears in Wednesday's Journal of the American Medical
Association and was released a day after another study that said that
being fat at 40 shortens a person's life by at least three years.
The JAMA study, led by University of Alabama at Birmingham
biostatistician David Allison, found that life expectancy for
20-year-olds with a body-mass index of at least 45 is 13 years lower for
white men and 20 years lower for black men, compared with people of
normal weight.
Body-mass index is a height-to-weight ratio; 30 and above is considered
obese. A person who is 5-foot-4 and 262 pounds would have a BMI of 45 --
and look like a sumo wrestler. But millions of Americans are that fat,
Allison said.
The life-shortening effects were found to be lower for 20-year-old
severely obese white women (eight years of life lost) and black women
(five years lost).
Obesity increases the risk for several life-threatening conditions,
including heart disease, diabetes and some types of cancer. Allison said
younger people are especially vulnerable, in part because they have more
years to live and more time for the obesity to take its toll.
Dr. JoAnn Manson of Harvard's Brigham and Women's Hospital said the
study helps emphasize that obesity is far worse than just "a cosmetic
problem."
Until this week, data attempting to quantify the effects of obesity on
life span were scarce.
In Tuesday's Annals of Internal Medicine, Dutch researchers presented
data on about 3,400 mostly white, middle-aged Americans. The researchers
found that being overweight at 40 is likely to reduce life expectancy by
at least three years -- as much, they said, as smoking cigarettes.
Obese, or severely overweight people, lost even more years -- about six
or seven.
The JAMA study was based on an analysis of nationally representative
surveys of more than 14,000 Americans.
Life-shortening effects were less dramatic in people who were less
obese. And there were startling racial differences in how fat people had
to be before life expectancy started to drop.
In blacks, life expectancy was not shortened in obese men with BMIs
under 31 and in obese women under 37. But in whites, reductions of about
one year occurred in young people who were merely overweight -- in men
with a BMI of about 25.5 and in women with a BMI of about 27.5.
BMIs between 25 and 30 are considered overweight; the ideal is between
18 and 25.
Allison said the reasons for the racial differences are unclear. But
some researchers have speculated that blacks may have relatively more
lean mass, or muscle, than fat.
A JAMA editorial said the differences may be due to limitations in the
study.
"It would be a great disservice to blacks if these results were used to
promulgate the concept that excess weight is not harmful to them," said
Manson and Shari Bassuk of Brigham and Women's Hospital.
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