[Pharmwaste] FW: Boys' birth defect is not increasing, raising questions about phthalate syndrome

Tenace, Laurie Laurie.Tenace at dep.state.fl.us
Fri Jul 10 10:02:33 EDT 2009


http://www.environmentalhealthnews.org/ehs/news/hypospadias-rates-stable 

Boys' birth defect is not increasing, raising questions about phthalate
syndrome 

Hypospadias, one of the most common birth defects among baby boys,
apparently is not increasing in the United States, casting doubt on
whether boys are harmed by phthalates and other endocrine-disrupting
chemicals thought to trigger reproductive abnormalities. 
By Marla Cone
Environmental Health News

July 10, 2009

Hypospadias, one of the most common birth defects among baby boys,
apparently is not increasing in the United States, casting doubt on
whether boys are harmed by phthalates and other endocrine-disrupting
chemicals thought to trigger reproductive abnormalities.

Researchers have reported that the hypospadias rate stayed the same in
New York State between 1992 and 2005. An earlier study also found no
increase in California boys between 1984 and 1997.

Hypospadias, a condition in which the urethra opening is on the
underside of the penis rather than the tip, occurs in roughly one of
every 250 male births. Surgery is normally required or the condition can
lead to infertility.

Some environmental scientists have suspected, based on studies of lab
animals, that exposure to chemicals that block testosterone may be
partially responsible for the birth defects.

In tests of lab rats, chemicals called phthalates, which are widely used
in plastic and personal care products, cause several reproductive
abnormalities that scientists have dubbed "testicular dysgenesis
syndrome" or "phthalate syndrome." Included are hypospadias, undescended
testes, reduced sperm counts and testicular cancer.

In the new study, New York Presbyterian Hospital urologists said that
because hypospadias rates are stable, it casts doubt on whether human
boys are harmed by phthalates or other endocrine-disrupting chemicals.

The researchers reported in the journal Urology that "these data suggest
that the testicular dysgenesis syndrome described in animal models may
not be evident in humans." The lead author was Dr. Harry Fisch, director
of the hospital's Male Reproductive Center and a professor of clinical
urology at Columbia University.

But other experts say the study does not invalidate the theory.

"The evidence seems to suggest that there hasn't been a big increase in
hypospadias over recent years, which does weaken the argument that new
endocrine disruptors in the environment are causing hypospadias," said
Kim Harley, a University of California, Berkeley epidemiologist who
studies environmental exposures and human health but was not involved
with the study.

Nevertheless, she added that it doesn't rule out that phthalates or
other chemicals have a role in causing the defects. Looking at how birth
defect rates change over time is not an adequate way of examining
environmental connections.

"Hypothetically, what if there were something that we were exposed to in
the past that also was associated with hypospadias? If that other
exposure were decreasing at the same time as phthalates were increasing,
it might wash out the effect and make rates stable over time," Harley
said. "That is why a study like this can only hypothesize based on time
trends, but can't make a one-to-one link between a chemical and a
disease."

Russ Hauser, a Harvard School of Public Health professor of
environmental and occupational epidemiology who studies phthalates and
other endocrine-disrupting chemicals, agreed. "There are many reasons
for why hypospadias may or may not have changed over time. Other risk
factors also change over time," he said.

The cause of hypospadias is unknown, but medical experts suspect that
something in the womb disrupts genes that regulate male hormones. A
variety of factors, including the mother's age, could be to blame. The
New York study found that hypospadias is more common in boys born to
mothers 35 years or older.

Although hypospadias may not be increasing now, several reports
previously noted a doubling of rates in the 1970s and 1980s.

Traces of many phthalates have been found in the urine of nearly every
human tested. One study, conducted in Germany, found that some of the
compounds have increased in people over the past 20 years, while others
have decreased, and that exposure varies greatly from place to place.
Some people exceed the daily levels that the U.S. Environmental
Protection Agency or European Food Safety Authority consider safe.

But whether the chemicals are harming people, particularly boys, has
become quite controversial in the past couple years.

Chemical industry representatives have pointed to the hypospadias study
as evidence that phthalates, which have been used as a plasticizer in
vinyl for about 50 years, are not causing male reproductive
abnormalities. In addition, while some studies have found that men's
sperm counts have declined substantially, others have reported no
decline, which also casts doubt on the human effects of endocrine
disruptors.

But Hauser said the hypospadias study does not invalidate the testicular
dysgenesis theory because no data was collected on the boys' exposure to
phthalates or other chemicals.

Researchers would need to collect exposure information on a large number
of pregnant women, and then see if the rate of hypospadias among the
highly exposed boys is different than those with low exposure, Hauser
and Harley said.

The findings are useful for exploring trends in hypospadias over time,
not exploring potential causes, they said.

"Over-interpretation should be avoided, especially using them to try to
prove a negative," Hauser said.

In addition to animal studies, other research has linked phthalates to
reproductive effects.

Hauser and his colleagues reported in 2006 that men with higher levels
of one common phthalate had lower sperm concentrations and quality. And
a study of 176 male infants by University of Rochester scientists found
that babies exposed to higher amounts of phthalates had a shorter
anogenital index (the length of the perineum), which is a sign of
feminized hormones.


Deborah L. DeBiasi 
Email:   Deborah.DeBiasi at deq.virginia.gov (NEW!)
WEB site address:  www.deq.virginia.gov 
Virginia Department of Environmental Quality 
Office of Water Permit Programs 
Industrial Pretreatment/Toxics Management Program 
PPCPs, EDCs, and Microconstituents 
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!) 
Location:  629 E. Main Street, Richmond, VA  23219 
PH:         804-698-4028 
FAX:      804-698-4032



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