title: Summary of fluoride studies
date: 2019-08-07
author: myauthor
url: http://www.somewhere.com

Introduction

• Updated: Aug 7, 2019
• URL:

A few notes before you get started.

1. Scientists and studies cannot say "this will happen" as nothing is 100% certain,
   so they say "this CAN happen"
   or "this COULD happen". This should not dilute the importance of the study findings
   in any way.

Basic facts

1. The impact of fluorine on human teeth was recognised in 1909 in
   Colorado, United States, when two dental surgeons, Frederick McKay and
   Grant Black, launched an investigation into the causes of mottled enamel
   (?Colorado brown stain?) in their practice area.[^swj2014]
2. Fluoride is normally introduced into drinking water via
   hexafluorosilicic acid.[^swj2014] Only city water is fluoridated, well water is not.
3. Currently, only about 5% of the world's population?350 million
   people?(including 200 million Americans) consume artificially fluoridated
   water globally. Only eight countries?Malaysia, Australia, USA, New
   Zealand, Singapore, and Ireland, more than 50% of the water supply
   artificially fluoridate.[^swj2014]
4. 97% of European countries do not fluoridate their drinking water yet
   tooth decay remains low.[^falert-europe]
5. 95% of US toothpaste contains fluoride. In fact,
   some stores don't even sell non-fluoridated toothpaste. All US toothpaste
   must come with a poison warning on the package. "Acute fluoride poisoning,
   which occurs at doses as low as 0.1 to 0.3 mg per kg of bodyweight,
   generally presents in the form of gastric pain, nausea, vomiting,
   headache, dizziness, and flu-like symptoms. (Akiniwa 1997; Gessner 1994)."[^falert-toothpaste]
6. Risks from ingesting fluoride toothpaste include permanent tooth
   discoloration (dental fluorosis), stomach ailments, acute toxicity, skin
   rashes (perioral dermatitis), and impairment in glucose
   metabolism.[^falert-toothpaste]
7. EPA headquarters Professional's Union opposes fluoridated water.[^falert-epaunion]
8. Studies about the brain:[^falert-brain]
   1. Over 200 animal studies showing that prolonged exposure to varying levels of fluoride can damage the brain, particularly when coupled with an iodine deficiency, or aluminum excess;
   2. 53 human studies linking moderately high fluoride exposures with reduced intelligence;
   3. 45 animal studies reporting that mice or rats ingesting fluoride have an impaired capacity to learn and/or remember;
   4. 12 studies (7 human, 5 animal) linking fluoride with neurobehavioral deficits (e.g., impaired visual-spatial organization);
   5. 3 human studies linking fluoride exposure with impaired fetal brain development.
   6. 3 Mother-Offspring studies linking certain levels of fluoride in the urine of pregnant women to reduced IQ in their offspring.
9. OSHA has set a legally enforceable limit of 0.2 milligrams per cubic
   meter (mg/m3) for fluorine, 2.0 mg/m3 for hydrogen fluoride, and 2.5
   mg/m3 for fluoride in workroom air to protect workers during an 8-hour
   shift over a 40-hour work week. (pdf page 32)[^atsdr2003]
10. NIOSH recommends air levels of 0.2 mg/m3
    for fluorine, 2.5 mg/m3 for hydrogen fluoride, and 2.5 mg/m3 for sodium
    fluoride in workroom air to protect workers during an 8-hour shift over a
    40-hour work week. (pdf page 32-33)[^atsdr2003]

What type of IQ tests could be used?

Some of the tests are the CRT-RC, Wechsler Intelligence test, Binet IQ test, or Raven?s test.

[^falert-toothpaste]: http://fluoridealert.org/issues/dental-products/toothpastes/. Accessed 2019-08-07.

[^falert-healtheffects]: http://fluoridealert.org/issues/health/. Accessed 2019-08-07.

[^falert-epaunion]: http://fluoridealert.org/articles/epa-union/. Accessed 2019-08-07.

[^falert-brain]: http://fluoridealert.org/issues/health/brain/. Accessed 2019-08-07.

More Fluoride studies, papers and results

Harvard 2012 study with children[^harvard2012]

[^harvard2012]: Developmental Fluoride Neurotoxicity: A Systematic Review
and Meta-Analysis. https://ehp.niehs.nih.gov/doi/10.1289/ehp.1104912,
https://doi.org/10.1289/ehp.1104912. Accessed 2019-08-07.
Supplemental material contains more links, like a biography.

• Link: "Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis". https://www.hsph.harvard.edu/news/features/fluoride-childrens-health-grandjean-choi/. Accessed 2019-08-07.

This meta-study eventually excluded some studies and ended up with 27 studies to analyze.

July 25, 2012 ? For years health experts have been unable to agree on
whether fluoride in the drinking water may be toxic to the developing
human brain. Extremely high levels of fluoride are known to cause
neurotoxicity in adults, and negative impacts on memory and learning have
been reported in rodent studies, but little is known about the
substance?s impact on children?s neurodevelopment. In a meta-analysis,
researchers from Harvard School of Public Health (HSPH) and China Medical
University in Shenyang for the first time combined 27 studies and found
strong indications that fluoride may adversely affect cognitive
development in children. Based on the findings, the authors say that this
risk should not be ignored, and that more research on fluoride?s impact
on the developing brain is warranted.

Search strategy. We searched MEDLINE (National Library of Medicine,
Bethesda, MD, USA; http://www.ncbi.nlm.nih.gov/pubmed), Embase (Elsevier
B.V., Amsterdam, the Netherlands; http://www.embase.com), Water Resources
Abstracts (Proquest, Ann Arbor, MI, USA;
http://www.csa.com/factsheets/water-resources-set-c.php), and TOXNET
(Toxicology Data Network; National Library of Medicine, Bethesda, MD, USA;
http://toxnet.nlm.nih.gov) databases to identify studies of
drinking-water fluoride and neurodevelopmental outcomes in children. In
addition, we searched the China National Knowledge Infrastructure (CNKI;
Beijing, China; http://www.cnki.net) database to identify studies
published in Chinese journals only. Key words included combinations of
?fluoride? or ?drinking water fluoride,? ?children,? ?neurodevelopment?
or ?neurologic? or ?intelligence? or ?IQ.? We also used references cited
in the articles identified. We searched records for 1980?2011. Our
literature search identified 39 studies, among which 36 (92.3%) were
studies with high and reference exposure groups, and 3 (7.7%) studies
were based on individual-level measure of exposures. The latter showed
that dose-related deficits were found, but the studies were excluded
because our meta-analysis focused on studies with the high- and
low-exposure groups only. In addition, two studies were published twice,
and the duplicates were excluded.

Conclusions: The results support the possibility of an adverse
effect of high fluoride exposure on children?s neurodevelopment. Future
research should include detailed individual-level information on prenatal
exposure, neurobehavioral performance, and covariates for adjustment.

Summary bullets:

1. Thus, children in high-fluoride areas had significantly lower IQ
   scores than those who lived in low-fluoride areas. Subgroup and
   sensitivity analyses also indicated inverse associations, although the
   substantial heterogeneity did not appear to decrease.[^harvard2012]

ATSDR toxicological profile for fluoride (part of CDC)

• Link: https://www.atsdr.cdc.gov/toxprofiles/tp11.pdf. Sep 2003. 404 pages.

This document has a lot of info and shows you what flouride compounds are used for.

Fluorides, hydrogen fluoride, and fluorine have been found in at least
188 of the 1,636 current or former NPL sites. However, the total number
of NPL sites evaluated for these substances is not known. As more sites
are evaluated, the sites at which fluorides, hydrogen fluoride, and
fluorine is found may increase. This information is important because
exposure to these substances may harm you and because these sites may be
sources of exposure.

Most studies have not found any association between fluoride and cancer in people.

Drinking or eating excessive fluoride during the time teeth are being
formed can cause visible changes in teeth. The condition is called dental
fluorosis. The changes increase in severity with increasing levels of
fluoride. Dental fluorosis develops only while the teeth are forming in
the jaw and before they erupt into the mouth (age <8 years). After the
teeth have developed and erupted, they cannot become fluorosed. Most
enamel fluorosis seen today is of the mildest form, in which there are a
few almost invisible white spots on the teeth. In moderate cases, there
are large white spots on the teeth (mottled teeth), and some brown spots.

Max levels of exposure

1. OSHA has set a legally enforceable limit of 0.2 milligrams per cubic
   meter (mg/m3) for fluorine, 2.0 mg/m3 for hydrogen fluoride, and 2.5
   mg/m3 for fluoride in workroom air to protect workers during an 8-hour
   shift over a 40-hour work week. (pdf page 32)
2. NIOSH recommends air levels of 0.2 mg/m3
   for fluorine, 2.5 mg/m3 for hydrogen fluoride, and 2.5 mg/m3 for sodium
   fluoride in workroom air to protect workers during an 8-hour shift over a
   40-hour work week. (pdf page 32-33)

Summary bullets

1. Teeth with too much fluoride can show white or brown spots.

[^atsdr2003]: https://www.atsdr.cdc.gov/toxprofiles/tp11.pdf. Sep 2003. 404 pages. Accessed 2019-08-07.

Developmental neurotoxicity of industrial chemicals.[^neurotox2016]

Results: The standardized weighted mean difference in IQ score between
exposed and reference populations was ?0.45 (95% confidence interval:
?0.56, ?0.35) using a random-effects model. Thus, children in
high-fluoride areas had significantly lower IQ scores than those who
lived in low-fluoride areas. Subgroup and sensitivity analyses also
indicated inverse associations, although the substantial heterogeneity
did not appear to decrease.

Summary bullets

[^neurotox2016]: "Developmental Fluoride Neurotoxicity: A Systematic Review
and Meta-Analysis." https://www.ncbi.nlm.nih.gov/pubmed/17174709.
Environmental Health Perspectives. 2006. Accessed 2019-08-07.
Also at https://doi.org/10.1289/ehp.1104912.

Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity.

• Reference: "Chronic administration of aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in neuronal and cerebrovascular integrity."
  https://www.ncbi.nlm.nih.gov/pubmed/9518651?dopt=Abstract. Accessed 2019-08-07.
• Ref: Varner JA, Jensen KF, Horvath W, Isaacson RL. Chronic administration of
  aluminum-fluoride or sodium-fluoride to rats in drinking water: alterations in
  neuronal and cerebrovascular integrity. Brain Res. 1998 Feb 16;784(1-2):284-98.
  PubMed PMID: 9518651.

This study describes alterations in the nervous system resulting from
chronic administration of the fluoroaluminum complex (AlF3) or equivalent
levels of fluoride (F) in the form of sodium-fluoride (NaF). Twenty seven
adult male Long-Evans rats were administered one of three treatments for
52 weeks: the control group was administered double distilled deionized
drinking water (ddw). The aluminum-treated group received ddw with 0.5
ppm AlF3 and the NaF group received ddw with 2.1 ppm NaF containing the
equivalent amount of F as in the AlF3 ddw. Tissue aluminum (Al) levels of
brain, liver and kidney were assessed with the Direct Current Plasma (DCP)
technique and its distribution assessed with Morin histochemistry.
Histological sections of brain were stained with hematoxylin & eosin (H&E),
Cresyl violet, Bielschowsky silver stain, or immunohistochemically for
beta-amyloid, amyloid A, and IgM. No differences were found between the
body weights of rats in the different treatment groups although more rats
died in the AlF3 group than in the control group. The Al levels in
samples of brain and kidney were higher in both the AlF3 and NaF groups
relative to controls. The effects of the two treatments on
cerebrovascular and neuronal integrity were qualitatively and
quantitatively different. These alterations were greater in animals in
the AlF3 group than in the NaF group and greater in the NaF group than in
controls.

Summary bullets

1. Aluminum fluoride could be more dangerous than sodium fluoride.

NRC (2006): Fluoride?s Neurotoxicity and Neurobehavioral Effects[^nrc2016]

[^nrc2016]: "NRC (2006): Fluoride?s Neurotoxicity and Neurobehavioral Effects". https://www.nap.edu/read/11571/chapter/9. Accessed 2019-08-07.
Copies at: http://fluoridealert.org/studies/brain06/, https://app.pagedash.com/p/56b6f0a8-ed3b-4a56-903d-1546c2f6f141/X4QCSSOFv7HcKwJEtrdK.
(Good list of studies!)

Several studies from China have reported the effects of fluoride in
drinking water on cognitive capacities (X. Li et al. 1995; Zhao et al.
1996; Lu et al. 2000; Xiang et al. 2003a,b). Among the studies, the one
by Xiang et al. (2003a) had the strongest design. This study compared the
intelligence of 512 children (ages 8-13) living in two villages with
different fluoride concentrations in the water. The IQ test was
administered in a double-blind manner. The high-fluoride area (Wamiao)
had a mean water concentration of 2.47 ± 0.79 mg/L (range 0.57-4.50
milligrams per liter [mg/L]), and the low-fluoride area (Xinhuai) had a
mean water concentration of 0.36 ± 0.15 mg/L (range 0.18-0.76 mg/L). The
populations studied had comparable iodine and creatinine concentrations,
family incomes, family educational levels, and other factors. The
populations were not exposed to other significant sources of fluoride,
such as smoke from coal fires, industrial pollution, or consumption of
brick tea. Thus, the difference in fluoride exposure was attributed to
the amount in the drinking water. Mean urinary fluoride concentrations
were found to be 3.47 ± 1.95 mg/L in Wamiao and 1.11 ± 0.39 mg/L in
Xinhuai. Using the combined Raven?s Test for Rural China, the average
intelligence quotient (IQ) of the children in Wamiao was found to be
significantly lower (92.2 ± 13.00; range, 54-126) than that in Xinhuai
(100.41 ± 13.21; range, 60-128).

The IQ scores in both males and females declined with increasing
fluoride exposure. The distribution of IQ scores from the females in
the two villages is shown in Figure 7-1. A comparable illustration of the
IQ scores of males is shown in Figure 7-2. The number of children in
Wamiao with scores in the higher IQ ranges was less than that in Xinhuai.
There were corresponding increases in the number of children in the lower
IQ range. Modal scores of the IQ distributions in the two villages were
approximately the same. A follow-up study to determine whether the lower
IQ scores of the children in Wamiao might be related to differences in
lead exposure disclosed no significant difference in blood lead
concentrations in the two groups of children (Xiang et al. 2003b).

Summary bullets

1. Flouride lowers IQ.[^nrc2016]

Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention[^swj2014]

[^swj2014]: "Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention".
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956646/, https://dx.doi.org/10.1155%2F2014%2F293019.
Accessed on 2019-08-07.

Although fluoride is used industrially in a fluorine compound, the
manufacture of ceramics, pesticides, aerosol propellants, refrigerants,
glassware, and Teflon cookware, it is a generally unwanted byproduct of
aluminium, fertilizer, and iron ore manufacture. The medicinal use of
fluorides for the prevention of dental caries began in January 1945 when
community water supplies in Grand Rapids, United States, were fluoridated
to a level of 1ppm as a dental caries prevention measure. However, water
fluoridation remains a controversial public health measure

In contrast, most studies reporting on the impact of water fluoridation on dental caries prevention appear to suggest that Dean and his colleagues ?proved? that water fluoridation reduces dental caries. For example, in a formal statement to commemorate 60 years of artificial water fluoridation, the American Dental Association stated

?Early studies, such as those conducted in Grand Rapids, showed that water fluoridation reduced the amount of cavities children get in their baby teeth by as much as 60% and reduced tooth decay in permanent adult teeth nearly 35%. Today, studies prove water fluoridation continues to be effective in reducing tooth decay by 20?40%??

Summary bullets

Study name

Summary bullets

Rejections of fluoride

Europe's rejections

• Reference: "Statements from European Health, Water, & Environment
  Authorities on Water Fluoridation".
  http://fluoridealert.org/content/europe-statements/. Accessed 2019-08-07.

[^falert-europe]: "Statements from European Health, Water, & Environment
Authorities on Water Fluoridation".
http://fluoridealert.org/content/europe-statements/. Accessed 2019-08-07.

At present, 97% of the western European population drinks
non-fluoridated water. This includes: Austria, Belgium, Denmark, Finland,
France, Germany, Greece, Iceland, Italy, Luxembourg, Netherlands,
Northern Ireland, Norway, Portugal, Scotland, Sweden, Switzerland, and
approximately 90% of both the United Kingdom and Spain. Wikipedia
confirms that these countries don?t fluoridate: Croatia, Estonia, Hungary,
Iceland, and Latvia. Although some of these countries fluoridate their
salt, the majority do not.

All study summary bullets

1. Thus, children in high-fluoride areas had significantly lower IQ
   scores than those who lived in low-fluoride areas. Subgroup and
   sensitivity analyses also indicated inverse associations, although the
   substantial heterogeneity did not appear to decrease.[^harvard2012]
2. Flouride lowers IQ.[^nrc2016], [^neurotox2016]

Links

1. DDG search
2. IARC fluoride page. Nothing found.
3. Pubmed search

Orgs

1. Fluoride Alert. http://fluoridealert.org/researchers/translations/complete_archive/
   Lots of good links and studies here.

More studies

1. Effect of high level of fluoride on children's intelligence
   JA An, SZ Mei, AP Liu, Y Fu, CF Wang - Chin J Control Endem Dis, 1992

[^def-smd]: SMD: standardized weighted mean difference

References