Study Links Air Pollutants With Autism

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Study Links Air Pollutants With Autism
2
Wed, 06-28-2006 - 7:17pm

* <http://uspirg.org/uspirgnewsroom.asp?id2=24977>*Four representative
study summaries and links follow the news item.

* * * *
*
Study Links Air Pollutants With Autism*
Bay Area children with the disorder are 50% likelier to be from areas
high in several toxic substances. Scientists say more research is needed.

By Marla Cone
Times Staff Writer
June 23, 2006
http://www.latimes.com/news/local/la-me-autism23jun23,1,732425.story

Children with autism disorders in the San Francisco Bay Area were 50%
more likely to be born in neighborhoods with high amounts of several
toxic air contaminants, particularly mercury, according to a
first-of-its-kind study by the California Department of Health Services.

The new findings, which surprised the researchers, suggest that a
mother's exposure to industrial air pollutants while pregnant might
increase her child's risk of autism, a neurological condition
increasingly diagnosed in the last 10 years.

But the scientists cautioned that the link they found in the Bay Area is
uncertain and that more definitive evidence would be needed before
concluding that mercury or any other pollutant could trigger autism.

Gayle Windham, the study's lead researcher and senior epidemiologist in
the department's environmental health investigations branch, called it
"a single small study" and "a first look" at whether toxic pollutants
play a role in the neurological disorder, which is often marked by poor
verbal and communication skills and withdrawal from social interaction.

Scientists have long wondered if the surge in diagnoses is due, in part,
to environmental causes. Some of the increase comes from growing doctor
and parent awareness, but experts say that cannot explain all of it.

"Clearly this suggests that there may be correlations between autism
onset and environmental exposures, especially as it relates to metal
exposures," said Isaac Pessah, a toxicologist who heads UC Davis' Center
for Children's Environmental Health and Disease Prevention. Pessah, who
was not involved in the study, is also a researcher at the university's
MIND (Medical Investigation of Neurodevelopmental Disorders) Institute,
which studies autism.

"It would be prudent to reserve judgment until we see if this study can
be replicated and whether it's of general significance" by looking for
the same link outside the Bay Area, he said.

About 300,000 U.S. children have been diagnosed with autism and often
need special education. The study compared 284 children from six Bay
Area counties who were diagnosed as having so-called autism spectrum
disorders --- which include a less-severe syndrome called Asperger's ---
with 657 children from the same counties without the disorders. All were
born in 1994.

The scientists reviewed data for 19 hazardous air pollutants that are
known or suspected neurotoxins: chemicals that have a toxic effect on
the brain.

They found that the children with the autism disorders were 50% more
likely than the non-autistic children to be born in areas with higher
estimated levels of three metals and two chlorinated solvents: mercury,
cadmium, nickel, trichloroethylene and vinyl chloride. No significant
link was found with 14 other solvents and metals, including compounds
such as lead, benzene and chromium.

The national autism rate is six children per 1,000, so a 50% increase
would elevate that rate to nine per 1,000.

The biggest increase came with heavy metals including mercury, a
pollutant from power plants, factories and mines that can disrupt brain
development.

The Bay Area was chosen for the study because extensive data are readily
available there because of a federally funded program to count and track
autistic children. The region's toxic air pollution is considered
typical for urban areas.

San Francisco County had the highest estimated levels of metals and
solvents, including mercury, and Marin County had the lowest of those
studied. But the researchers did not compare autism prevalence by county.

In their report, published online Wednesday in the journal Environmental
Health Perspectives, the authors said their research "suggests that
living in areas with higher ambient levels of hazardous air pollutants,
particularly metals and chlorinated solvents, during pregnancy or early
childhood, may be associated with a moderately increased risk of autism.
These findings illuminate the need for further scientific investigation,
as they are biologically plausible but preliminary and require
confirmation."

The study is the first to look for a connection between autism among
children and levels of hazardous air pollutants at birth. Last year,
scientists who compared volumes of industrial mercury emissions in Texas
with autism in schoolchildren reported a similar link.

Autism is believed to start in the womb, early in pregnancy, when the
brain develops. Genetic factors determine who is susceptible, but
experts theorize that environmental factors contribute.

The new study found that mercury was the "most significant correlation
with autism," Pessah said, "but every family may not be affected the
same way because of their genetic makeup."

Many parents of autistic children blame vaccines that contained a type
of mercury called thimerosal. Expert reviews have found no link between
vaccines and autism, but some scientists do not consider them definitive.

No assumptions about vaccines can be made on the basis of the air
pollution study. "Mercury in the air is a different type than in
vaccines," Windham said.

The new study examined elemental mercury, which is released into the air
from coal-burning power plants, chlorine factories and gold mines. It
spreads globally and builds up in food chains, particularly in oceans.
Levels of mercury are increasing in many parts of the world, largely
from power plants in China and India.

The researchers had not expected to be able to discern a relationship
between autism and the air pollution data.

The five metals and solvents are common industrial pollutants, but air
is only one source of exposure, because they also contaminate water and
food.

Some experts say that if there is a link between mercury and autism, it
most likely comes from fish consumption, the main route of mercury
exposure. A 20-year, ongoing study in Denmark's Faroe Islands has shown
that children have slightly reduced intelligence when mothers consumed
excessive mercury in seafood.

The largest limitation or uncertainty in the Bay Area study is that the
pollution data did not come from measurements of compounds to which the
mothers were actually exposed. Instead, they were based on estimates
calculated by the U.S. Environmental Protection Agency using computer
modeling of industrial emissions.

Windham said that "there could be other explanations" for the link they
found. For example, it could be that women who live in the
worst-polluted areas also smoke more or eat more contaminated seafood.
The scientists did not track down the mothers to compare lifestyles.

Researchers at Johns Hopkins University's School of Public Health are
conducting a similar study in the Baltimore area to see if they
replicate the findings.

*

*Twenty-eight states more than doubled their carbon dioxide emissions
between 1960 and 2001, according to a new analysis of government data*
Increased combustion of oil to fuel cars and light trucks and coal for
electricity drove the steep rise in emissions. Among the states, Texas
ranked first in the nation for the highest emissions of carbon dioxide
in 2001, releasing 12% of the nation's total. *
The Carbon Boom <http://uspirg.org/uspirgnewsroom.asp?id2=24977>

**At least 180 human diseases and health conditions are linked by human
research to environmental exposures.* Of 198 diseases surveyed, 123 have
strong links to exposures. The majority of chemicals have not been
tested for potential toxic effects, even those some are commonly found
in contexts that will lead to human exposures.
*CHE Toxicant and Disease Database.
<http://database.healthandenvironment.org/intro.cfm>*

*A metal refinery, Eramet Marietta, is a top polluter in the Mid-Ohio
Valley.* A citizen audit finds that this facility produces ten times
more manganese in dust than its sister facility in Norway, and tens of
thousands of pounds more pollution going into local waterways. *
Citizens' Audit of Eramet Marietta
<http://www.ohiocitizen.org/campaigns/eramet/Citizen%20Audit%20final%20master.pd\
f>

**Harmful toxic pollutants were found in the bodies of every child and
parent tested in a national study in Canada.* Of the 68 chemicals
measured, sixty-eight percent were detected. Children had higher levels
of some chemicals than their parent, including PFCs, PBDEs, heavy
metals, OP pesticides and PAHs. *
Polluted Children , Toxic Nation.
<http://www.environmentaldefence.ca/pressroom/releases/2006/20060601.htm>*

*

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Avatar for littleroses
iVillage Member
Registered: 03-28-2003
Wed, 06-28-2006 - 10:56pm

iVillage Member
Registered: 03-26-2003
Wed, 06-28-2006 - 11:27pm

And the quicker they make difinitive conclusions the quicker we can get to definitive treatments.

Gotta say, chelation is looking more and more appealing. If they can just give me 100% safety and 100% effectiveness, lol.

Renee

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