Data suggest no clear line in obesity
risk
March 13, 2005
By Raja Mishra
Precautions apply to spectrum of children studied
Some children considered lean by government standards
still face a significantly elevated risk for becoming
obese or overweight adults and for developing high blood
pressure, according to new Harvard research that challenges
the notion that a clear line separates at-risk children
from healthy children.
For years, physicians and researchers have neatly categorized
people as obese, overweight, or healthy-weight, with
the assumption that each group faces different health
risks. But the new research indicates that matters are
far more fluid, particularly for children.
''Most of our health risks are really on a gradient.
. . . There's no bright line dividing healthy from unhealthy
weights," said Dr. Matthew W. Gillman, associate
professor of ambulatory care and prevention at Harvard
Medical School and an author of the new study. ''When
we make decisions about people, we often have to create
categories. . . . In reality, these things are on a
spectrum."
Researchers have long known that obese children often
become obese adults, at high risk for heart disease,
diabetes, and cancer. But the new study, published online
last week in the journal Obesity Research, indicates
that parents of children not considered overweight also
must be wary of weight gain in their children. All the
diet and exercise precautions that apply to overweight
children should apply to many leaner children as well,
the study's authors said.
''We need to monitor children." said Alison Field,
an assistant professor of pediatrics at Children's Hospital
Boston and another author of the study. ''Even if they're
within the normal weight range but moving up, that should
be a cause for concern,. Just because they haven't crossed
into the overweight category, doesn't mean they're not
at risk."
The study, which followed 314 East Boston children
for more than a decade, found that children on the heavier
end of the healthy-weight bracket, as defined by the
government, are still five times as likely as leaner
children to become overweight or obese adults. Moreover,
some children in this so-called healthy category were
four times as likely to develop high blood pressure
as adults.
The federal government categorizes people by weight
using the Body Mass Index, or BMI, which is calculated
by dividing a person's weight in pounds by height in
inches squared, multiplied by 703.
Children have long been categorized by the percentile
of the index into which they fall, with heavier children
in higher percentiles. Children with index scores falling
between the 85th and 95th percentiles are considered
overweight. Those in the 95th percentile or higher are
considered obese. The new study found that children
in the lower percentiles are also at risk for a future
of health problems.
''Those between the 50th and 75th percentile were five
times as likely to be overweight as adults" as
those below the 50th percentile, Fields said.
The study also found that children falling in the 75th
to 84th percentiles were four times as likely as those
below the 50th percentile to develop high blood pressure
as adults, which would put them at risk for heart disease
and stroke. Many of the high blood pressure cases found
in the study began early in adulthood, a particularly
disturbing trend, the study's authors said.
''We used to think of hypertension and diabetes as
problems of older age," Fields said. ''Now, we're
seeing them in younger and younger kids."
The new study is one of the few that managed to follow
a population of children through adulthood, made possible
in part by the relative stability of neighborhoods in
East Boston. Often, attempts at such studies collapse,
because researchers cannot track down children when
they become adults and scatter about the country. But
the Harvard team was able to find almost all the original
participants who were first studied as children between
1978 and 1981.
Gillman, who handled much of the detective work, said,
''We were able to find our original participants through
neighbors and local records."
Source:www.boston.com
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