MONDAY, June 17 (HealthDay News) -- Fetal exposure to the
chemical bisphenol A (BPA) has been linked to low levels of a key
developmental hormone in newborn boys with undescended testicles,
according to an early new study.
The research adds to the list of growing health concerns related
to BPA, which is widely used in food packaging. Government studies
have shown that 92 percent of Americans have detectable levels of
BPA in their bodies.
This study focused on boys with cryptorchidism, the medical term
for undescended testicles. The condition occurs in 2 percent to 5
percent of newborn boys, according to the authors, and requires
surgery to bring the testes out of the abdominal cavity. Boys born
with cryptorchidism have an increased risk of fertility problems
and testicular cancer in adulthood.
The researchers found that boys with cryptorchidism who had high
levels of BPA in their fetal cord blood also had low levels of the
hormone insulin-like 3, or INSL3, one of two hormones that regulate
descent of the testicles.
The findings do not draw a direct link between BPA and
cryptorchidism, as the newborns with undescended testicles did not
have greatly increased levels of BPA compared with newborns without
the birth defect.
Researchers found, however, that the BPA level in newborns' cord
blood inversely correlated with the level of INSL3. That is, the
higher the BPA level, the lower the level of the important
The study was presented Sunday at the Endocrine Society's annual
meeting in San Francisco. The data and conclusions should be viewed
as preliminary until published in a peer-reviewed journal.
"Alone, our study cannot be considered as definitive evidence for an environmental cause of undescended testis," lead author Dr. Patrick Fenichel, professor and head of reproductive endocrinology at the University Hospital of Nice, in France, said in a society news release. "But it suggests, for the first time in humans, a link that could contribute to one co-factor of [unexplained] undescended testis, the most frequent congenital malformation in male newborns."
This appears to be the first study that shows a link between
INSL3 levels and BPA, said Shanna Swan, a professor and vice chair
for research and mentoring in the department of preventive medicine
at the Icahn School of Medicine at Mount Sinai, in New York
"This hormone INSL3 has not been, to my knowledge, previously linked to any endocrine-disrupting chemicals," Swan said. "It's interesting, definitely, and it's an important step."
For the study, Fenichel and his colleagues studied 180 newborn
boys between 2003 and 2005, including 52 boys born with one or two
undescended testicles. They tested the infants' umbilical cord
blood to measure levels of BPA and INSL3.
The infants with cryptorchidism had significantly lower levels
of INSL3 compared to newborns without the birth defect, the authors
reported. Fenichel speculated that BPA, considered a hormone
disruptor, might repress expression of the gene that promotes
production of INSL3.
The U.S. Food and Drug Administration has banned the use of BPA
in products such as baby bottles and sippy cups, but the chemical
continues to be used in many other consumer products.
The most prominent continuing use of BPA is in the lining of
aluminum and tin cans, where it prevents corrosion. "The linings of
tin cans is probably the biggest source of our exposure," Swan
said. "There is almost no canned food that comes in BPA-free
BPA also is found in cash register receipts. "To have a cash
register receipt that doesn't require ink, it is coated in BPA,"
Swan said, noting that studies have found increased BPA levels in
the urine of people who have touched a receipt.
Both Swan and Dr. Leonardo Trasande, an associate professor of
pediatrics, environmental medicine and health policy at NYU Langone
Medical Center in New York City, noted that there are limitations
to the new study.
BPA typically is not measured in blood, Trasande and Swan said.
In most cases, doctors use urine to measure BPA exposure.
Swan also said the study does not make a clear link between BPA
and undescended testicles, since BPA levels appeared consistent in
all the newborns regardless of whether they had the birth
"That said, you have to [ask], What is INSL3 related to?" she added. "It is definitely related to descent of the testicles, and required for descent of the testicles."
Trasande said the study "certainly raises another set of health
concerns that haven't been raised before about BPA exposure."
"While research is needed to study exposure to BPA during pregnancy and risk of birth defects to confirm this association, it also adds further concern about the ongoing decision by the Food and Drug Administration not to ban BPA in food uses," Trasande said.
To learn more about BPA, visit the
U.S. National Institute of Environmental Health
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