Chinese children drinking well water with very high levels of fluoride scored poorly on intelligence testing

Wang SX, ZH Wang, XT Cheng, J Li, ZP Sang, XD Zhang, LL Han, SY Qiao,
ZM Wu and ZQ Wang. 2007. Arsenic and fluoride exposure in drinking
water: children's IQ and growth in Shanyin County, Shanxi province,
China. Environmental Health Perspectives 115(4):643-7.


July 5, 2007
Context
What did they do?
What did they find?
What does it mean?
Resources
More new science from EHN


Synopsis by Sheela Sathyanarayana and Wendy Hessler

Chinese children drinking well water with very high levels of fluoride
scored poorly on intelligence testing compared to those with lower
exposures.

This is one of the first studies in humans to find that too much
fluoride is associated with low performance on intelligence tests.
More information is needed to ascertain if the sum total amount of
ingested fluoride from tap water, consumer products and other sources
are enough to inhibit brain development in children living in the US
and other countries where fluoridation is common.
Chinese students taking test.

http://ilena-rosenthal.blogspot.com



http://www.environmentalhealthnews.o...5wangetal.html

Context: Fluoride is a recommended additive to public water supplies
to promote healthy teeth. The Centers for Disease Control and
Prevention reports that 66% of the US population receives fluoridated
water through the taps in their homes. Fluoride combats tooth decay in
two ways. It strengthens tooth enamel, and it allows teeth damaged by
acid to repair, or remineralize, themselves.

Excessive fluoride intake can have negative consequences on bone,
teeth and the brain. Too much of the ion can lead to skeletal
fluorosis, a condition in which teeth have weak enamel and bones have
poor mineralization.

Exposure to high levels of fluoride may also alter brain development,
according to recent studies of Chinese populations . Studies from
rural China, albeit done with inappropriate controls, suggest fluoride
may harm the developing brain (Grandjean and Landrigan 2006). Young
children are the most vulnerable to the neurodevelopmental effects
from too much fluoride (Xiang et al. 2003).


What did they do? Wang et al. examined 524 children (exposed and
controls) aged 8 to 12 years old in China's Shanxi province for
fluoride exposures in relation to intellectual functioning and growth.
The families were exposed to naturally occurring high concentrations
of fluoride through well water. The children were compared to control
children who were recruited from three nearby villages with uniformly
low concentrations of fluoride in well water. All children lived in
areas with similar geography, cultural conditions and socioeconomic
development.

The authors obtained urine samples for fluoride analyses and conducted
physical exams. Medically trained professionals administered
standardized neurodevelopmental tests.

What did they find? Very high fluoride concentrations -- as high as
8.3 milligrams per liter (mg/L) -- were measured in the well water of
the high fluoride group while the control group's well water had just
0.5 mg/L of fluoride.

The percentage of children with IQ scores less than 70 increased from
0 in the control group to 4% in the high fluoride group. The
percentage of children with IQ scores greater than 109 was 41% in the
control group and decreased to 30% in the high fluoride group.
Overall, children in the high fluoride group had a four-point
reduction in IQ score as compared to the control children. Measured
fluoride in the urine was almost five times higher in the high
fluoride exposed children than in the controls (5.1 mg/L versus 1.5
mg/L in controls). All of these associations were statistically
significant.



What does it mean? Fluoride may affect brain development in growing
children exposed to high levels of the ion through drinking water.
Lower overall IQ scores, a greater number of lower scores and fewer
higher scores were found in the group of children drinking high
fluoride well water when compared with children who drank well water
with lower amounts of fluoride. The observed differences in testing
could affect a child's ability to perform in school.

The results have significant public health implications given that tap
water and many other products contain fluoride. It may be that many
children are receiving high of doses of fluoride in the US. The
drinking water concentrations of fluoride observed in this study are
likely well above concentrations in US public drinking water supplies,
but children may be receiving excess fluoride through multiple sources
(drinking water, soft drinks/bottled water, toothpaste, mouth rinses).

At this time, there are no studies quantitating the sum of all
fluoride exposures for an average child in the US. The American Dental
Association has recommended that infants not be given formula
reconstituted with fluoridated water to prevent excess exposures.
Further studies should measure all fluoride exposures to children to
prevent fluorosis and potential neurodevelopmental toxicities.

On Jul 5, 11:25 am, Ilena Rose wrote:
Wang SX, ZH Wang, XT Cheng, J Li, ZP Sang, XD Zhang, LL Han, SY Qiao,
ZM Wu and ZQ Wang. 2007. Arsenic and fluoride exposure in drinking
water: children's IQ and growth in Shanyin County, Shanxi province,
China. Environmental Health Perspectives 115(4):643-7.

July 5, 2007
Context
What did they do?
What did they find?
What does it mean?
Resources
More new science from EHN

Synopsis by Sheela Sathyanarayana and Wendy Hessler

Chinese children drinking well water with very high levels of fluoride
scored poorly on intelligence testing compared to those with lower
exposures.

This is one of the first studies in humans to find that too much
fluoride is associated with low performance on intelligence tests.
More information is needed to ascertain if the sum total amount of
ingested fluoride from tap water, consumer products and other sources
are enough to inhibit brain development in children living in the US
and other countries where fluoridation is common.
Chinese students taking test.

http://ilena-rosenthal.blogspot.com

http://www.environmentalhealthnews.o...2007-0705wange...

Context: Fluoride is a recommended additive to public water supplies
to promote healthy teeth. The Centers for Disease Control and
Prevention reports that 66% of the US population receives fluoridated
water through the taps in their homes. Fluoride combats tooth decay in
two ways. It strengthens tooth enamel, and it allows teeth damaged by
acid to repair, or remineralize, themselves.

Excessive fluoride intake can have negative consequences on bone,
teeth and the brain. Too much of the ion can lead to skeletal
fluorosis, a condition in which teeth have weak enamel and bones have
poor mineralization.

Exposure to high levels of fluoride may also alter brain development,
according to recent studies of Chinese populations . Studies from
rural China, albeit done with inappropriate controls, suggest fluoride
may harm the developing brain (Grandjean and Landrigan 2006). Young
children are the most vulnerable to the neurodevelopmental effects
from too much fluoride (Xiang et al. 2003).

What did they do? Wang et al. examined 524 children (exposed and
controls) aged 8 to 12 years old in China's Shanxi province for
fluoride exposures in relation to intellectual functioning and growth.
The families were exposed to naturally occurring high concentrations
of fluoride through well water. The children were compared to control
children who were recruited from three nearby villages with uniformly
low concentrations of fluoride in well water. All children lived in
areas with similar geography, cultural conditions and socioeconomic
development.

The authors obtained urine samples for fluoride analyses and conducted
physical exams. Medically trained professionals administered
standardized neurodevelopmental tests.

What did they find? Very high fluoride concentrations -- as high as
8.3 milligrams per liter (mg/L) -- were measured in the well water of
the high fluoride group while the control group's well water had just
0.5 mg/L of fluoride.

The percentage of children with IQ scores less than 70 increased from
0 in the control group to 4% in the high fluoride group. The
percentage of children with IQ scores greater than 109 was 41% in the
control group and decreased to 30% in the high fluoride group.
Overall, children in the high fluoride group had a four-point
reduction in IQ score as compared to the control children. Measured
fluoride in the urine was almost five times higher in the high
fluoride exposed children than in the controls (5.1 mg/L versus 1.5
mg/L in controls). All of these associations were statistically
significant.

What does it mean? Fluoride may affect brain development in growing
children exposed to high levels of the ion through drinking water.
Lower overall IQ scores, a greater number of lower scores and fewer
higher scores were found in the group of children drinking high
fluoride well water when compared with children who drank well water
with lower amounts of fluoride. The observed differences in testing
could affect a child's ability to perform in school.

The results have significant public health implications given that tap
water and many other products contain fluoride. It may be that many
children are receiving high of doses of fluoride in the US. The
drinking water concentrations of fluoride observed in this study are
likely well above concentrations in US public drinking water supplies,
but children may be receiving excess fluoride through multiple sources
(drinking water, soft drinks/bottled water, toothpaste, mouth rinses).

At this time, there are no studies quantitating the sum of all
fluoride exposures for an average child in the US. The American Dental
Association has recommended that infants not be given formula
reconstituted with fluoridated water to prevent excess exposures.
Further studies should measure all fluoride exposures to children to
prevent fluorosis and potential neurodevelopmental toxicities.

--------------- Sh-h-h-h-h ! --------------------

Christ all ****in' mighty! Don't spread this stuff around! The
chinks'll start shipping "pure natural spring water" to the U.S. at 50-
cents a bottle!

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