Pizza here I come!
http://www.nytimes.com/2007/11/07/health/07fat.html?em&ex=1194498000&en=5aced1dd3fdd1ec2&ei=5087%0A
Causes of Death Are Linked to a Persons Weight
By GINA KOLATA
About two years ago, a group of federal researchers reported that
overweight people have a lower death rate than people who are
normal weight, underweight or obese. Now, investigating further,
they found out which diseases are more likely to lead to death in
each weight group.
Linking, for the first time, causes of death to specific weights,
they report that overweight people have a lower death rate because
they are much less likely to die from a grab bag of diseases that
includes Alzheimers and Parkinsons, infections and lung disease.
And that lower risk is not counteracted by increased risks of dying
from any other disease, including cancer, diabetes or heart
disease.
As a consequence, the group from the Centers for Disease Control
and Prevention and the National Cancer Institute reports, there
were more than 100,000 fewer deaths among the overweight in 2004,
the most recent year for which data were available, than would have
expected if those people had been of normal weight.
Their paper is published today in the Journal of the American
Medical Association.
The researchers also confirmed that obese people and people whose
weights are below normal have higher death rates than people of
normal weight. But, when they asked why, they found that the
reasons were different for the different weight categories.
Some who studied the relation between weight and health said the
nation might want to reconsider what are ideal weights.
If we use the criteria of mortality, then the term overweight is
a misnomer, said Daniel McGee, professor of statistics at Florida
State University.
I believe the data, said Dr. Elizabeth Barrett-Connor, a
professor of family and preventive medicine at the University of
California, San Diego. A body mass index of 25 to 30, the so-called
overweight range, may be optimal, she said.
Others said there were plenty of reasons that being overweight was
not desirable.
Health extends far beyond mortality rates, said Dr. JoAnn Manson,
chief of preventive medicine at Brigham and Womens Hospital in
Boston.
Dr. Manson added that other studies, including ones at Harvard,
found that being obese or overweight increased a persons risk for
any of a number of diseases, including diabetes, heart disease and
several forms of cancer. And, she added, excess weight makes it
more difficult to move about and impairs the quality of life.
Thats the big picture in terms of health outcomes, Dr. Manson
said. Thats what the public needs to look at.
Researchers generally divide weight into four categories normal,
underweight, overweight and obese based on the body mass index,
which is a measure of body fat based on height and weight. A woman
who is 5 foot 4, for instance, would be considered at normal weight
at 130, underweight at 107 pounds, overweight at 150 pounds and
obese at 180.
In this study, those with normal weight were considered the
baseline and others were compared to them.
The federal researchers, led by Katherine Flegal, of the Centers
for Disease Control and Prevention, said the big picture they found
was surprisingly complex. The higher death rate in obese people, as
might be expected, was almost entirely driven by a higher death
rate from heart disease.
But, contrary to expectations, the obese did not have an increased
risk of dying from cancer. They were slightly more likely than
people of normal weights to die of a handful of cancers that are
thought to be related to excess weight cancers of the colon,
breast, esophagus, uterus, ovary, kidney and pancreas. Yet they had
a lower risk of dying from other cancers, including lung cancer. In
the end, the increases and decreases in cancer risks balanced
out.
As for diabetes, it showed up in the death rates only when the
researchers grouped diabetes and kidney disease as one category.
Diabetes can cause kidney disease, they note. But, the researchers
point out, the number of diabetes deaths may be too low because
many people with diabetes die from heart disease, and often the
cause of death is listed as a heart attack.
The diverse collection of diseases other than cancer, heart disease
and diabetes, which show up in the analyses of the underweight and
the overweight, have gone relatively unscrutinized among
epidemiologists, noted Dr. Mitchell Gail, a cancer institute
scientist and an author of the paper. But, Dr. Gail added, these
are not a negligible source of mortality.
The new study began several years ago when the investigators used
national data to look at death risks according to body weight. They
concluded that, compared with people of normal weight, the
overweight had a decreased death risk and the underweight and obese
had increased risk.
That led them to ask if being fat or thin affects a persons life
span, what diseases, exactly, are those individuals at risk for, or
protected from?
The research involved analyzing data from three large national
surveys, the National Health and Nutrition surveys, which are
administered by the National Center for Health Statistics. Their
participants are a nationally representative group of Americans who
are weighed and measured, assuring that heights and weights are
accurate, and followed until death. The investigators determined
the causes of death by asking what was recorded on death
certificates.
The researchers caution that a study like theirs cannot speak to
cause and effect. They do not yet know, precisely, what it is about
being underweight, for instance, that increases the death rate from
everything except heart disease and cancer. Researchers tried to
rule out those who were thin, because they might have been already
sick. They also ruled out smokers, and the results did not
change.
Dr. Gail, though, had some advice, which, he said, is his personal
opinion as a physician and researcher: If you are in the pink and
feeling well and getting a good amount of exercise and if your
doctor is very happy with your lab values and other test results,
then I am not sure there is any urgency to change your
weight.
