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 Some soaps, nail polish, hairspray, shower curtains, raincoats, car
interiors and dryer sheets contain phthalates, which are used as
so-called plasticizers, or softening agents.
At present, the Food and Drug Administration does not have evidence
that phthalates as used in cosmetics pose a safety risk, but six
types of phthalates are currently banned from children’s toys,
according to the U.S. Consumer Product Safety Commission.
There are no regulations on a pregnant woman’s exposure to the
chemicals, and phthalates are usually not labeled on products in the
U.S.
“This is the only study looking at this in a longitudinal fashion,”
said lead author Pam Factor-Litvak, a professor at Columbia
University’s Mailman School of Public Health in New York, noting
that this study only observed a relationship and did not test cause
and effect.
“I think that there would need to be more studies to build up
causation,” Factor-Litvak said.
Researchers followed 328 New York women in low-income communities
from pregnancy until the child was seven years old.
During late pregnancy, researchers tested the women’s urine for di-n-butyl
phthalate (DnBP), di-isobutyl phthalate (DiBP), di-2-ethylhexyl
phthalate and diethyl phthalate.
When the children were seven, they completed an intelligence test
measuring four areas of mental functioning.
The mothers’ levels of two of the phthalates - DnBP and DiBP -
during pregnancy were associated with childhood intelligence: As
phthalate levels went up, child IQ tended to go down.
When the researchers divided the mothers into four groups based on
the amount of phthalates in their urine, kids whose mothers had the
highest levels had an intelligence quotient (IQ) score about seven
points lower than kids whose mothers had the lowest levels of the
chemicals in their urine, according to the results in PLOS ONE.
The difference persisted when the authors accounted for other
factors that can influence IQ, including the mother’s IQ, her
alcohol use during pregnancy, education, marital status and the
child’s birth weight.
“With observational studies, there is always the chance that the
results may be in part explained by an unmeasured factor that we
haven’t yet considered,” said Stephanie Engel, associate professor
of epidemiology at UNC Gillings School of Global Public Health in
Chapel Hill, North Carolina.
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“I would characterize this study as thorough and high quality, and
the results concerning,” said Engel, who was not involved in the
work. “But there needs to be more research in this area before firm
conclusions can be drawn.”
Nevertheless, on a population level, six IQ points is a very
significant shift, she told Reuters Health.
“It is clear that there needs to be a serious discussion in the
scientific and policy communities about whether the evidence is
strong enough yet to warrant widespread policy changes, not just on
the basis of this study, but also including a range of childhood
health outcomes that have already been reported in the literature,”
Engel said.
Phthalates and similar chemicals, including bisphenol A (BPA), have
also been associated with childhood obesity and asthma.
Factor-Litvak and her coauthors previously looked at the possible
effects on motor skills in three-year-old children, and the results
were similar.
Although there are no regulations on phthalate exposure during
pregnancy, it would be prudent for expectant mothers to avoid
microwaving food in plastic, avoid scented products, avoid plastics
labeled #3, #6 or #7, and as much as possible store foods in glass
instead of plastic, she said.
It might be prudent for everyone, not just pregnant women, to take
note of these chemicals, she said.
“Because they are so ubiquitous it’s very hard to avoid right now
but you can reduce your use of those products as much as possible,”
she told Reuters Health.
Based on animal studies, researchers have several theories about how
phthalates might affect development, including disrupting sex
hormones, thyroid hormones or dopamine-sensitive activity in the
brain, she said.
SOURCE: http://bit.ly/1Bz1Dcj PLOS ONE, online December 10, 2014.
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