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E-M:/ Chemicals may be linked to learning disabilities
- Subject: E-M:/ Chemicals may be linked to learning disabilities
- From: Tracey Easthope <firstname.lastname@example.org>
- Date: Wed, 23 Jun 2004 12:13:26 -0400
- Delivered-To: email@example.com
- Delivered-To: firstname.lastname@example.org
- List-Name: Enviro-Mich
- Reply-To: Tracey Easthope <email@example.com>
Title: Chemicals may be linked to learning
The press release below is from a press
briefing that was held yesterday in Washington DC. Of interest
to Enviro-mich readers is the discussion about synthetic chemicals in
the environment, like PBDE's, PCB's and dioxins, and their potential
contribution to reduced levels of maternal thyroid hormones or
abnormal thyroid function. Thyroid levels in the mother are
critical to healthy brain development in children, and disruption
could result in learning and developmental disabilities in
The experts are calling for thyroid
screening as a part of routine health care for all pregnant women and
women who are planning to have children.
Maternal Thyroid Disorder Linked
Children's Learning Disabilities
Experts Call for Thyroid Testing for Expectant Mothers;
Toxic Chemicals Said to Exacerbate Problem
Washington -- Citing a scientific study linking abnormal
thyroid-related hormone levels in expectant mothers with developmental
problems in their babies, a panel of experts today recommended thyroid
screening as part of routine health care for all pregnant women and
women who are planning to have children.
The experts referred to a study published in the New England
Journal of Medicine finding that children 7-8 years old had I.Q.
scores 7 points lower if their mothers had slightly low thyroid
hormone levels or even normal thyroid hormone with slightly elevated
levels of thyroid stimulating hormone- a condition known as
subclinical hypothyroidism - during pregnancy.
"Thyroid hormone is essential for fetal brain development,"
said Ted Schettler, a physician at the Boston Medical Center and
science director for the Science and Environmental Health Network.
"We've known for a long time that obvious thyroid deficiency can
impair normal brain development but it's the children of mothers
without symptoms that we need to worry about as well. We ought to be
more aggressively looking for subclinical hypothyroidism in mothers
because it's affecting the neurological development of
In subclinical hypothyroidism, the mother does not exhibit symptoms of
hypothyroidism but the fetus may still be affected. Two and one-half
percent of pregnant women are subclinically hypothyroid and 100,000
babies are born each year to these women, Schettler said.
James Haddow, professor of pediatrics at the University of Vermont
School of Medicine and lead author of the study in the New England
Journal of Medicine, said that, once detected, the problem can be
easily corrected with a daily pill.
"Hypothyroidism is a perfect example of something that's easy and
inexpensive to detect and to treat once it's detected," said
Haddow. "It makes good sense to incorporate [thyroid screening]
into prenatal care."
Jane Browning, executive director of the Learning Disabilities
Association of America, called on doctors to make thyroid screening a
routine part of a well-woman exam, and said it should be part of every
pre-pregnancy and pregnancy exam.
Browning discussed her experience raising a developmentally disabled
child. Her son recently graduated with a high school certificate at
age 21. Because of his disability, he requires a professional
companion and assistance with basic tasks such as showering and
"You think it's hard to find a job
without a college degree. Try finding work without a high school
diploma," said Browning. "The cost to families is high. The
cost to society is high. It's twice as expensive, for society, to
school someone who has a learning disability."
"Moms and moms-to-be, please make sure
you get your thyroid level tested," Browning urged. She said home
testing kits are available for expectant mothers who cannot find a
doctor to provide a test.
The panelists said synthetic chemicals in the environment may be
contributing to reduced levels of maternal thyroid hormones or
abnormal thyroid hormone function. "There are classes of
compounds in the environment that effect thyroid function in ways we
could not have imagined 10 years ago. In the lab we're seeing what
appear to be links between some of these compounds and brain
development which could result in learning and developmental
disabilities in humans," said Thomas Zoeller, professor of
biology at the University of Massachusetts.
PCBs, perchlorate from rocket fuel, and a class of flame retardants
called PBDEs are all known to interfere with the thyroid gland or
thyroid hormone function. PBDEs in particular have received a great
deal of attention in the press, as studies have found high levels of
the chemicals in household dust and in the human body.
"We have had an extraordinary rise in
PBDEs throughout the population," said Schettler, referring to
the presence of these synthetic chemicals in the human body.
Schettler said that PBDEs are very similar to PCBs, which have been
banned in the United States since 1976, and should be treated as an
equal threat and replaced with safer alternatives . "There's no
need to repeat the same mistake we made with PCBs," he