
Prenatal Fluoride Exposure and Cognitive Outcomes in Children - vixen99
https://ehp.niehs.nih.gov/ehp655/
======
mchannon
Looking at the shotgun blasts they had been able to produce, I'm disappointed
there wasn't a clearer signal. Take out the 130 IQ kid with little fluoride
and the three kids with high fluoride and slightly-below-average IQ's and you
might even be able to predict a beneficial effect to fluoride.

To clear up a few of the other questions, they didn't measure where mama was
getting her fluoride, or how much was in her tap water, or even how effective
she was at excreting it. They also didn't measure postnatal fluoride exposure
by the children, which may be less, more, or just as important.

Mama could have swallowed some toothpaste or mouthwash even though she lived
on unfluoridated water. She could have eaten a steady diet of fluoride-infused
potato chips manufactured in a place with fluoridated water even though her
water was unfluoridated. Or, she could have been a tea drinker, which is a
leading source of fluoride.

Absent evidence to the contrary, I believe this study's conclusions are the
right ones, but the study could do little to back them up. For all we know
(and for all the efforts the study didn't make to rule it out), higher
fluoride exposure could simply be a reflection of poverty, which would
similarly correlate to lower childhood IQ's.

If you drink untreated water in Mexico, you may very well be drinking
fluoridated water, which occurs naturally in some spots. El Paso and
Albuquerque have naturally fluoridated water.

~~~
klakier
They adjusted the results for the excretion ratio (adjusted for urinary
creatinine and specific gravity, respectively).

Note that at least in Europe the toothpastes for children contain no fluoride.

~~~
bobthechef
Some brands of toothpaste substitute fluoride with xylitol. There is evidence
that it hardens enamel.

[https://www.ncbi.nlm.nih.gov/pubmed/14700079](https://www.ncbi.nlm.nih.gov/pubmed/14700079)

[https://www.sciencedirect.com/science/article/pii/S091723940...](https://www.sciencedirect.com/science/article/pii/S0917239404700099)

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asdffinio
Oh, boy. This will be fun.

To the (many) people in this comments section who seem unable to read, here's
the conclusion of the study:

"Community water and salt fluoridation, and fluoride toothpaste use,
substantially reduces the prevalence and incidence of dental caries (sic)
(Jones et al. 2005) and is acknowledged as a public health success story
(Easley 1995). Our findings must be confirmed in other study populations, and
additional research is needed to determine how the urine fluoride
concentrations measured in our study population are related to fluoride
exposures resulting from both intentional supplementation and environmental
contamination. However, our findings, combined with evidence from existing
animal and human studies, reinforce the need for additional research on
potential adverse effects of fluoride, particularly in pregnant women and
children, and to ensure that the benefits of population-level fluoride
supplementation outweigh any potential risks."

This is a preliminary study that doesn't even _try_ to establish a causal
connection between water fluoridation and intelligence. It suggests an avenue
of future research. It's not a license to assert whatever fringe beliefs you
want. The evidence is that water fluoridation is safe and effective. Maybe
future studies will change that, but those studies have yet to be done.

We should all be skeptics. Dismissing the consensus in favor of conspiracy
theories is not skepticism. It is blind credulity.

------
nordsieck
They found a 2 IQ point difference testing kids 6-12 years old with a sample
size of 500. I'm not sure why I'm supposed to believe anything in this study.

I understand that it's expensive to run longer studies, but with an effect
size of 2 IQ points, they'd really have to test the kids post puberty at a
minimum. Otherwise the numbers will just be too volatile.

~~~
swebs
500 sounds like a sufficient sample size to me. How many samples would you
need before accepting the results of a study?

~~~
nordsieck
It's not necessarily any one aspect of the study, but all of the elements as a
whole.

1\. This is an observational study, not a double blind experiment. We know
that these are basically garbage. In many cases it's unethical to do
experiments, so observation is the best we have; that doesn't mean it's any
good.

2\. IQ pre puberty is highly volatile. The younger you test, the less your
results correlate with eventual adult IQ.

It may be possible to add say 100x more participants to compensate for the 2nd
point. You can't add more participants to fix the first point; blacklisting
confounders just doesn't work except in exceptional cases (e.g. smoking and
cancer).

The real way to do this study is

1\. Double blind study instead of observation. This means along with
everything they're already doing, they need to give the mothers a 16 year
supply of water filters (presumably over time). Half of them would be inert.

2\. Run the study until the kids are at least 16.

Yes, this is more expensive, but the knowledge per dollar gained would be
infinitely higher.

~~~
dpark
> _but the knowledge per dollar gained would be infinitely higher._

Would it be? It sounds like millions, potentially tens of millions, would be
required to run this hypothetical study. And the likely outcome is that the
effect is minimal.

~~~
nordsieck
>> but the knowledge per dollar gained would be infinitely higher.

> Would it be?

I meant that literally. 1/4x is infinitely larger than 0/x

> And the likely outcome is that the effect is minimal.

Everyone knew this was true before the study started.

~~~
dpark
I misunderstood. I thought you were saying the knowledge would be worth
infinitely more than the millions this would cost.

------
stillbourne
[https://www.ada.org/en/publications/ada-
news/2017-archive/se...](https://www.ada.org/en/publications/ada-
news/2017-archive/september/ada-responds-to-study-suggesting-association)

------
mrfusion
Where does toothpaste fall on this scale?

~~~
FrozenVoid
Fluoride toothpastes sold in the U.S. generally contain between 1,100 and
1,450 parts per million (ppm) fluoride (the equivalent of over 1 mg of
fluoride for each gram of paste). [http://fluoridealert.org/issues/dental-
products/toothpastes/](http://fluoridealert.org/issues/dental-
products/toothpastes/)

~~~
mrfusion
Is that enough to lower intelligence? I couldn’t seem to figure it out from
the paper.

~~~
ashildr
Maybe if you change your brand of toothpaste you will?

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patrickg_zill
Supposedly fluoridation leads to a change in the pineal gland, which is a
partially understood part of the brain. Any truth to that?

------
bobthechef
But why fluoridate? Why add fluoride to the water supply? Even IF it helps
prevent tooth decay and even IF we knew there were no harmful side effects,
how is that a reason? Why not add something to make hair shinier? Or your
breath smell fresh? Or something for heart disease? It's such an arbitrary
thing to add to water. Besides, with fluoride in toothpaste, what's the point?

I would prefer that nothing were added to tap water. Leave it alone.

~~~
seandougall
Dental health is not just cosmetic; it affects multiple areas of physical
health. If there were a safe way to add something that would prevent heart
disease, it would absolutely be in the public interest. Your other examples
are strawmen.

You can certainly argue (as this paper’s conclusion does) that more research
is needed on other potential effects of fluoridation, but it isn’t arbitrary.

~~~
teaspoons
and fluoridation doesn't affect dental health because you're drinking the
water which means the fluoride doesn't get to the teeth but is absorbed
elsewhere in the body. If you want fluoride you can get it through toothpaste.
It should be a choice.

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johnaspden
So, does it turn out that all those nut jobs who _ignored science_ and claimed
that putting a neurotoxin in the water supply was a bad thing might have had a
point?

~~~
linedash
No; it turned out that bad studies produce not very useful statistics.

Others in this thread have already indicated why this study doesn't help with
much. Unfortunately it will just give the anti-fluoride crowd ammunition.

~~~
bobthechef
Why don't Europeans fluoridate?

~~~
kurthr
Because they have working public health systems?

Actually, I think it's a pretty personal and difficult question to answer
that's unlikely to be uniform across Europe. Perhaps it's because they drink
more tea and coffee which themselves have high fluoride levels (~3-5x
fluoridated water levels in the US?

[http://fluoridealert.org/issues/sources/tea/](http://fluoridealert.org/issues/sources/tea/)

------
jakeogh
Conventional wisdom is often wrong.

------
SagelyGuru
Are teeth more important than brain? Only when your real interest is to sell
more sugary drinks and processed sugary foods. Sugar is cheap and addictive
and if you somehow fix the tooth decay, it is your "perfect product".

Serious questions need to be asked about the World Health Organisation for
supporting and pushing fluoridation globally.

~~~
matthewmacleod
This is a conspiracy theory view which isn’t worth giving much consideration
to.

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vixen99
The title I supplied was " More research on potential adverse effects of
fluoride is needed" and was taken from the paper. Not sure how the actual
paper title appeared.

------
mcculley
This makes me wonder if fluoride could be a cause of the rise in autism.

------
FrozenVoid
Where are those fluoride shills, proclaiming the great benefits of
involuntrary medicating everyone to improve teeth by osmosis(fluoride is
applied topically)? Sooner or later, this will be on the same page of history
as asbestos and leaded fuel.

~~~
matthewmacleod
I mean there is _pretty_ compelling evidence that water fluoridation reduces
tooth decay in children. I’m not clear what your objection is - are you
suggesting this is not the case?

~~~
sjg007
Do kids really need fluoride before their adult teeth start to grow in?

~~~
philliphaydon
Not really. Tooth paste for kids generally doesn’t contain fluoride to begin
with. But it’s still important to get kids into the habit of brushing and
prevent gum disease.

