Home' Trinidad and Tobago Guardian : June 20th 2013 Contents B18
Guardian www.guardian.co.tt Thursday, June 20, 2013
Living in an area with high levels
of air pollution may increase a
woman s chances of having a child
with autism, according to the first
national study to date that investigates
the possible link.
"Women who were exposed to the
highest levels of diesel or mercury in
the air were twice as likely to have a
child with autism than women who
lived in the cleanest parts of the sam-
ple," study author Andrea Roberts, a
research associate with the Harvard
School of Public Health, told The Huff-
Earlier studies have established a
potential connection between air pol-
lution and autism risk, but have con-
centrated on a few individual states.
The latest study, published in the jour-
nal Environmental Health Perspectives
on Tuesday, draws on a large sample
of women across the whole country.
Researchers crossed US Environmen-
tal Protection Agency data on the level
of air pollutants from year to year with
data from the Nurses Health Study,
one of the longest running investiga-
tions of women s health in the US. They
looked for associations between levels
of pollutants in the time and place that
a woman was pregnant and whether
that woman went on to have a child
with a diagnosed autism spectrum dis-
The researchers split up the locations
into fifths, and women who lived in
the most polluted sections---those with
the highest levels of diesel particulates
or mercury in the air---were twice as
likely to have a child with autism com-
pared to those in the cleanest sections.
Other types of air pollution, including
lead, manganese and other hard metals,
were also linked to a greater risk of
autism, although the risk was not quite
"All of the chemicals studied are
known neurotoxins," Roberts said.
"They are also known to pass from
mother to baby while a woman is preg-
nant. It s very plausible that the stuff
the mother is taking in through the air
is affecting her baby s brain develop-
But the researcher cautioned against
reading too much into the results, par-
ticularly with regard to mercury. Many
parents continue to worry that the
form of mercury sometimes used in
vaccines is linked to autism---although
that claim has been repeatedly dis-
proven by research efforts.
"Our data is not good enough to
know which thing in the air might
actually be causing this (link), if it even
is something in the air that is increasing
the risk of autism," Roberts said. "It
might be that it s actually diesel that s
(behind) the problem. We are skeptical
about the possibility of mercury being
causal in this way, through the air."
Alycia Halladay, the senior director
for environmental and clinical sciences
for the advocacy group Autism Speaks,
said that "in terms of how (air pollu-
tion) is linked to autism, that s not
something we re able to specifically
"We can make a lot of hypotheses,
but we don t really know," added Hal-
laday, who did not work on the study.
The next step, which would repre-
sent a crucial step forward, is to look
at blood samples of both mothers and
their babies to see what chemicals are
actually being absorbed, Roberts said.
Only then can researchers assert with
any real certainty that the link exists,
and begin to understand which specific
air pollutants are the most damaging.
The cause of autism is not yet
known, although researchers suspect
that a combination of genetic and non-
genetic factors, such as parental age
and complications during pregnancy
could all play a role.
For now, there are few specific steps
women living in high-pollution areas
can take in order to mitigate their risk.
"There are things any doctor or
health care professional would tell you
to do," Halladay said. Those include
eating well, taking a prenatal vitamin,
getting regular prenatal health care
check-ups and staying away from sick
people or viruses as much as possible.
"This is just a change in risk," she
said, "it s certainly not a cause."
Study links autism
to air pollution
High levels of air
of having a child
Other types of air
other hard metals,
were also linked
to a greater risk
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