Tuesday, April 06, 2004
By Lauran Neergaard, Associated Press
WASHINGTON — Does a pregnant woman's exposure to certain chemicals
put her child at risk of learning disabilities? Do genetics and
pollution interact to cause asthma? What's the real impact of TV
on toddlers?
The government is preparing the largest study of U.S. children
ever performed — it will track 100,000 from mothers' wombs to age
21 — to increase understanding of how the environment affects youngsters'
health.
It's called the National Children's Study, and pediatric specialists
say it is coming at a crucial time. Rates of autism, asthma, certain
birth defects, and other disorders are on the rise, as is concern
about which environmental factors play a role. And technology has
finally advanced enough to allow study of multichemical and gene-environment
interactions that might explain why some children seem at greater
risk.
The study "really represents our generation's best hope of
coming to learn the environmental causes of these conditions,"
said Dr. Philip Landrigan, an expert on children and the environment
at New York's Mount Sinai School of Medicine.
It's a quest to prove both what's harmful and what's not.
"There are things we probably should be worrying about that
we're not worrying about enough, and there are things we're worrying
about too much," said Landrigan, who is advising the National
Institute of Health on the study's design.
The study, ordered by Congress in 2000, is in its late planning
stages. Enrollment of pregnant women is set for 2006, although proponents
hope three pilot sites could begin work late next year. Already
families alerted by interested patient-advocacy groups are asking
how to participate.
The question is money. Scientists say they need $27 million to
$50 million next year to ramp up, including hiring a laboratory
big enough to store more than 2 billion anticipated biological and
environmental samples, from participants' blood and DNA to dust
from their houses, soil from their yards, and air from their neighborhoods.
Congress has provided roughly $12 million annually for three years
of study preparation. President Bush requested the same amount for
next year, and budget constraints have lawmakers indicating they're
unlikely to provide more.
A partnership of strange bedfellows is lobbying for more. The industry's
American Chemistry Council, which expects the study to vindicate
some of its products, is pairing with environmentalists and patient
and doctor groups, who argue that the study will help fight diseases
that cost billions every year.
The study's ultimate cost over two decades is $2.7 billion.
The last major child-health study, in the 1960s, tracked the children
of 55,000 pregnant women until age 7 to learn the causes of cerebral
palsy. It also yielded other important discoveries, such as that
doctors at the time weren't properly treating infants' fever-caused
seizures.
The National Children's Study is to be far more encompassing. Director
Dr. Peter Scheidt of NIH's National Institute of Child Health and
Human Development outlines its overall aims:
* To measure environmental exposures of concern and hunt differences
by degree of exposure.
Chemicals and pollutants top the list. Scheidt cites a Minnesota
study that found signs of pesticide exposure in the urine of 85
percent of children tested. But does exposure equal harm? Another
example: chemicals such as phthalates, which soften plastic, may
affect hormones to cause male birth defects or encourage early puberty.
Other environmental influences studied may include day care, diet,
early-life infections, and television.
* To study health problems specifically suspected of environmental
links in hopes of pinpointing risk factors.
For example, studies of genetically identical twins show when one
twin gets Type 1, or juvenile, diabetes, the other has just a 50
percent of getting it. Genes put these children at risk, but something
else, perhaps a virus, pushes them over the edge.
Brain development is another huge concern, and some substances
can harm a developing brain in subtle ways and tiny amounts. Only
recently have scientists learned to measure low-level contaminant
exposure and to show not only that a person was around something
toxic but that it actually absorbed into their DNA. And then there
are windows of vulnerability: An exposure may harm during one month
of pregnancy but not another.
* Storing genetic and other health and exposure data long-term
to test future questions without starting from scratch.
"The kinds of information we'll be collecting ... will provide
an enormously valuable resource for doing this kind of research
for decades to come," Scheidt said.
Source: Associated Press
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