WORLD / Health
Obese survive heart attacks better
(AP)
Updated: 2007-07-10 10:29
LONDON - While being fat increases your chances of a heart attack, some
studies suggest a puzzling paradox: Obese people seem to have a better
chance of surviving one. Scientists are stumped over why that seems to be
the case and pose several theories.
There may be physiological differences in the hearts of obese and
normal-weight people. Or perhaps it depends on where the fat is on their
bodies.
However, experts warn, the results should not be used as an excuse for
the overweight to indulge.
"We really don't want people to think that they should put on a bit of
weight to have a better chance with their bypass surgery," said Dr.
Gerald Fletcher, a cardiologist at the Mayo Clinic in Florida and a
spokesman for the American Heart Association.
"These results do not mean it's OK to be fat. Being fat is still
dangerous to your health for lots of other reasons," Fletcher said.
A 2005 study published in the American Journal of Medicine by scientists
at Duke University examined nearly 16,000 people in 37 countries. The
authors found that one year after a heart attack, the death rate for
normal-weight patients was 4.3 percent. For obese patients, it was just
2.2 percent.
Several other studies have confirmed those findings, including a paper
last month in the European Heart Journal. German and Swiss doctors
tracked more than 1,600 patients for three years after their heart
attacks, and concluded that only 3.6 percent of fat patients had died,
against nearly 10 percent of normal-weight patients.
"We don't have a good explanation for the biological phenomenon that's
causing this," said Dr. Eric Eisenstein, leader of the Duke study. "We
need to understand scientifically what's happening in these folks before
we can develop new therapies."
There is a higher prevalence of smoking among thin patients, one possible
explanation. But even after statistically adjusting for that, fat
patients still had a distinct advantage, researchers found.
Some experts suggest it depends on where the fat is located, noting that
fat around the abdomen is the biggest risk. Other doctors think there may
be physiological differences in the heart.
"It could be that the hearts of obese people are 'pre-conditioned'
because they're under more stress in the first place," said Dr. Andrew
Newby, a professor of vascular biology at Bristol Heart Institute and
spokesman for the European Society of Cardiology. Newby said that fat
people who had heart attacks might be better able to withstand the
initial shock to the system.
Dr. Rob Califf of Duke University said the survival rate difference
between fat and thin "is not a big enough factor" to make changes in
patient care. Other signs such as the magnitude of the heart attack and
whether patients have kidney problems are more important in predicting
survival, he said.
But experts say it is important to better understand the fat-thin paradox
so doctors can provide better treatment.
Some suggested that fat people who have heart attacks can markedly
improve their survival odds if they make some major lifestyle changes, an
option that normal-weight patients may not have.
"Even moderate weight loss can have a big impact," said Dr. Heinz
Buettner of the Heart Centre in Bad Krozingen in Germany. "Obese patients
have a better chance to correct their situation compared to thin patients
who may just have bad genes."
Because obesity can lead to other dangers - including high blood
pressure, diabetes, and cancer - the apparent survival advantage fat
people have after a heart attack might be erased by something worse down
the line.
"Obese patients may get lucky after one heart attack, but they are still
high-risk patients," said Fletcher. "If they stay fat after their
surgery, they could end up back in the hospital soon and more bad things
could happen."
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