Setting the Record Straight on Fluoride

Dr. Richard ValachovicIn this month’s letter, ADEA President and CEO Dr. Rick Valachovic explains why community water fluoridation—a public health intervention most of us take for granted—is under attack as never before.

It has been called one of the 10 great public health achievements of the 20th century, yet 70 years after its introduction in the United States, community water fluoridation can no longer be taken for granted. Opponents of fluoridation continue to advocate for the removal of fluoride from water supplies, and they have found some interesting allies.

Just this past summer, Israel’s Health Minister Yael German ended a decades-long government policy that mandated public water fluoridation in communities of 5,000 or more inhabitants. This occurred despite vocal opposition from the Israeli Dental Association, the academic community, public health experts and the country’s Prime Minister, Benjamin Netanyahu. German acknowledged that fluoride is beneficial in preventing dental caries but defended her actions on the grounds that she believes fluoride may be harmful to certain groups and that administering it through the water system infringes on personal rights.

I’m sure I don’t need to tell any of you of the massive amount of credible scientific evidence that has demonstrated again and again that optimally fluoridated water is safe to drink, does not cause systemic disease and provides the best protection against dental caries in both children and adults over the course of a lifetime. Dental fluorosis, a change in the appearance of tooth enamel that does not endanger health, is the only proven outcome associated with ingesting too much fluoride. Severe fluorosis rarely occurs in communities where the amount of fluoride in the water is in keeping with the standards set by the Centers for Disease Control and Prevention (CDC).

Despite this strong body of research, opponents of fluoridation assert that fluoride is linked to health problems ranging from cancer to diabetes to thyroid disease. Recently, they have touted the findings of a study published in 2012 in Environmental Health Perspectives to support their call for eliminating water fluoridation. The study is a systematic review and meta-analysis of the possible effects of fluoride on children’s neurodevelopment. The authors found that “children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas,” and concluded that these “results support the possibility of an adverse effect of high fluoride exposure on children’s neurodevelopment.”

It’s important to note that the children in question did not reside in New York, Ontario, Jerusalem or other places where fluoride was added to the water at ratios considered optimal for improving oral health. The vast majority of the data in the reviewed studies came from China, where considerably higher levels of fluoride occur naturally in the drinking water of many communities. As the authors of the paper point out, the exposed groups in the studies they reviewed had access to drinking water with fluoride concentrations up to 11.5 milligrams per liter, so in many cases, fluoride concentrations exceeded the levels recommended in the United States for improving oral health (0.7–1.2 milligrams per liter) or allowed by the Environmental Protection Agency (4.0 milligrams per liter).

Nevertheless, anti-fluoridation activists seized on the paper as evidence against community water fluoridation, and they used the Harvard affiliation of the paper’s lead author, a research scientist in the university’s School of Public Health, to bolster the credibility of their cause. These misrepresentations of the paper’s findings led the Dean of the Harvard School of Dental Medicine, Bruce Donoff, D.M.D., M.D., and the Dean of the Faculty of Medicine at the Harvard Medical School, Jeffrey Flier, M.D., to issue a letter in 2013 expressing their support for community water fluoridation and pointing out the “numerous reputable studies” reinforcing its safety and efficacy.

Setting the record straight is essential and will require an energetic response from all of us who are in a position to make scientific evidence easy to understand for the public at large. A report in the Journal of the Massachusetts Dental Society found that opponents of community water fluoridation dominate Internet and social media discussions of the topic. Moreover, some research suggests than many Americans are inclined to believe in medical conspiracy theories in general.

In a letter to JAMA Internal Medicine published earlier this year, two political scientists from the University of Chicago reported that 12% of Americans agree with this statement: “Public water fluoridation is really just a secret way for chemical companies to dump the dangerous byproducts of phosphate mines into the environment.” Perhaps more disturbing, fewer than half of respondents disagreed with the statement, which means there is an urgent need to steer people toward reliable sources of accurate information so they can play an informed role in decision-making around this crucial aspect of the public health infrastructure.

The CDC is an excellent place to start. The agency’s Community Water Fluoridation FAQs explain how fluoride works when added to drinking water and topical products such as toothpaste, and discuss the potential adverse effects from overexposure in clear and unbiased terms. Another Department of Health and Human Services site, the Guide to Community Preventive Services, has links to a 2013 systematic review of the evidence on which it bases its support of community water fluoridation as well as a summary of the rationale for supporting the intervention. The Campaign for Dental Health, a program of the American Academy of Pediatrics, has developed guides for health professionals on fluoride safety and guides for consumers and patients as well.

These resources provide plenty of evidence to counter the misinformation circulating about fluoride, but they do little to blunt the argument that community water fluoridation deprives individuals of their freedom to decide whether or not they want to use fluoride to protect their teeth. The Fluoride Action Network (FAN), the leading advocacy group opposed to fluoridation, quotes one of its congressional supporters, Rep. Dana Rohrabacher (R-CA): “[I]n this country, we should be the ones who should be deciding what we put into our bodies one way or the other. Not the federal government or the local government putting fluoride into our water. A lot of those things come down to freedom issues. They come down to whether or not we will control our own destiny.”

This type of rhetoric is reminiscent of the culture wars that have divided Americans around other issues related to health. Last month, public television’s premier science program, NOVA, devoted an hour-long show to the shift in attitudes toward vaccination that has led to recent outbreaks of measles and pertussis—diseases that were so well controlled in North America that physicians had difficulty believing what they were seeing when the first 21st-century cases appeared.

The rise in dental disease that follows the cessation of water fluoridation is harder to spot than a sudden outbreak of highly contagious disease, but it is visible nonetheless to those who know where to look. In Calgary, Alberta, where the City Council voted to stop fluoridating the drinking water in 2011, dentists say they have already seen a noticeable increase in the severity of dental caries in their patients’ teeth.

It may take a few years before we see the impact of the recent decision by the Israeli Ministry of Health. (The new policy does not ban fluoridation despite what some headlines might suggest, just makes it optional.) Moving forward, the ministry plans to address the oral health needs of the public by instituting a number of health promotion programs. These are aimed at educating pregnant women, parents, preschool teachers, health care providers and school-age children about oral health.

These types of efforts are all to the good, but researchers have found that they are neither as effective nor as affordable as community water fluoridation when it comes to decreasing the prevalence and severity of dental caries. Importantly, community water fluoridation is also a powerful strategy for eliminating oral health disparities. As the CDC stated in hailing the practice as a public health success, “Although other fluoride-containing products are available, water fluoridation remains the most equitable and cost-effective method of delivering fluoride to all members of most communities, regardless of age, educational attainment, or income level.”

Last month, FAN held its first lobby day in Washington, D.C., and called on Congress to hold joint congressional hearings on water fluoridation. FAN wants Congress to stop spending taxpayer money to promote fluoridation through the CDC. FAN would also like the Food and Drug Administration to regulate ingested fluoride as a drug, and the Environmental Protection Agency to reevaluate its standard for the maximum allowable level of fluoride in drinking water.

While opponents and proponents of community water fluoridation may disagree on what constitutes the best available scientific evidence, it is worth noting that we share a mutual concern about the health of future generations and a desire to see science guide public health decision-making. It is up to those of us in the academic dental community to continue contributing to and disseminating solid research. Through our contact with patients, we also have an opportunity to educate the public at large about the overall benefits of fluoride and water fluoridation specifically. This may be at least one effective way to help put public fears to rest.

Today, three quarters of U.S. communities—with the notable exception of Portland, Oregon, whose citizens voted once again to prohibit fluoridation of the city’s drinking water in 2013—provide residents with fluoridated water, as do all major U.S. cities. About 45% of Canadians have access to fluoridated water, but regional variations are significant.

ADEA supports and encourages fluoridation of community water supplies and the use of topical fluoride. So do the American Dental Association, the International Association of Dental Research, the National Institute of Dental and Craniofacial Research and the World Health Organization.

Former U.S. Surgeon General Dr. C. Everett Koop once said, “I encourage the dental profession in communities which do not enjoy the benefits of an optimally fluoridated drinking water supply to exercise effective leadership in bringing the concentration to within an optimum level.” Today he might say that dental professionals in all communities need to lead on this issue. I know that ADEA members will be in the vanguard.

13 comments
  1. John S Findley, DDS said:

    One of the best overall statements on community water fluoridation ever written! While we as a profession understand and “rest” in the science of the fluoride argument, it is most important for our profession to understand that fluoridation is being significantly challenged today and that we cannot relax because we are supported by science. Science is not always the determining factor in decisions by public bodies – politics and emotional argument can sometimes overpower science and even common sense. That said, it is and should be the duty of each of us in the profession to understand that the threat of anti-fluoridationists is real and that it is not enough for us to just understand the science fluoridation, we must stand-up and be able to clearly, accurately and understandably communicate the facts of fluoridation to decision-makers and opinion-makers in each of our own communities. Dr. Valachovic’s article provides a clear explanation and will serve as a valuable resource in addressing current and future challenges to improving and protecting the oral health of all our people.

    • Steve Slott said:

      I agree, Dr. Findley. Dr. Valachovic’s comments are well written and right on target…….just as are yours. Our complacency with the status of fluoridation has led to a constant flow of misinformation being disseminated by FAN, in this country and several others. Our profession needs to challenge this at every opportunity, with facts and evidence. But we need to ensure that we sre knowledgeable and fully understanding of this issue in so doing.

      A couple of tweaks to Dr. Valachovic’s comments. Israeli Minister of Health, German, is an antifluoridationist from before her days as mayor of an Israeli community. She fought against fluoridation then and has carried her ideology into her current position. The Israeli healthcare community has vehemently fought her on this unilateral decision to cease fluoridation, and was successful in at least getting her to modify her position to allow for communities to have the option to fluoridate if they so choose.. Unfortunately, though, the Minister reneged on this agreement right at the deadline, and declined to allow even optional fluoridation. The incensed Israeli healthcare community currently has legal action against her in court, with the hope and expectation that the courts will force her to reverse her irresponsible action. Time will tell. However, given that her decision has gone against the advice and recommendations of her own healthcare experts, her decision is hardly anything to which antifluoridationists, including FAN, can point as being validation of their fabricated health concerns of fluoridation. It is simply the abuse of power by one, single Israeli, elected official who has imposed her personal ideology on an entire country.

      In regard to the support of the Deans of the Harvard Schools of Medicine and Dental Science, the Dean of the Harvard School of Public Health, Julio Frenk, MD, MPH, PhD, also singned onto that letter in support of fluoridation. Of much significance is that Dr. Frenk is Philippe Grandjean’s superior in the School of Public Health. As for the 27 Chineses studies, by Grandjean’s and Choi’s own admission in their Review, these studies had missing key information, inadequate controls, and questionable methodologies. They were so flawed thst Grandjean and Choi were compelled to issue the following statement in 2012:

      “–These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S. On the other hand, neither can it be concluded that no risk is present. We therefore recommend further research to clarify what role fluoride exposure levels may play in possible adverse effects on brain development, so that future risk assessments can properly take into regard this possible hazard.”

      –Anna Choi, research scientist in the Department of Environmental Health at HSPH, lead author, and Philippe Grandjean, adjunct professor of environmental health at HSPH, senior author

      As it seems there have been no translations of these studies into English by any reliable, objective source, it is unclear as to whether they had even been peer-reviewed, a basic for credibility of any scientific study. These studies were flawed that nothing could be “concluded” from them.

      As far as the recommendation for further research, which should always be recommended on any scientific matter, such further research has been done, by Broabent, et al. In a study published in the May, 2014 edition of the American Journal of Public Health, Broadbent found:

      “Results. No significant differences in IQbecause of fluoride exposurewere noted. These findings held after adjusting for potential confounding variables, including sex, socioeconomic status, breastfeeding, and birth weight (as well as educational attainment for adult IQ outcomes).”

      “Conclusions. These findings do not support the assertion that fluoride in the context of CWF programs is neurotoxic. Associations between very high fluoride exposure and low IQ reported in previous studies may have been affected by
      confounding, particularly by urban or rural status”

      Community Water Fluoridation and Intelligence: Prospective Study in New Zealand
      Jonathan M. Broadbent, PhD, W. Murray Thomson, BSc, PhD, Sandhya Ramrakha, PhD, Terrie E. Moffitt, PhD,
      Jiaxu Zeng, PhD, Lyndie A. Foster Page, BSc, PhD, and Richie Poulton, PhD

      (Am J Public Health. Published online ahead of print May 15, 2014: e1–e5. doi:10.2105/AJPH.2013.30185

      To the surprise of no one, antifluoridationists have been quick to attack this study, seeking to minimize its impact. Considering their full embrace of the flawed Chinese studies, however, this effort can easily be seen as nothing more than a highly hypocritical and transparent ploy on the part of these activists.

      The public health initiative of water fluoridation prevents dental decay, with no proven adverse effects in its entire 69 year history. It’s that simple.

      Steven D.Slott, DDS

  2. SP Zusman, DMD. said:

    Excellent article. One inaccuracy: adding fluoride to water in Israel is prohibited and not optional. The restitution of fluoride to desalinated water is illegal too at present.
    Dr. Findley’s comment is very correct: “Science is not always the determining factor in decisions by public bodies”.

  3. Jana S Winfree, DDS said:

    Science appears to be irrelevant for many: for every credible source supporting CWF, there are readily available, always in hand, counter sources expressing doubt. It’s truly challenging to play point counterpoint with the public and the media, so avoid the debate. It’s best to calmly stick to the facts and common sense. The long list of organizations and medical supporters of CWF is appreciated – such as the American Academy of Pediatrics – people respect those that treat children. Also, along with politics and emotion, economic factors play a significant role in communities ceasing or not implementing fluoridation. The value of CWF is generally not acknowledged by local officials and the cost to purchase, repair and maintain equipment, the availability and cost of fluoride additives, and the non-desirable task of monitoring is often mentioned by those that work in water treatment plants as reasons they would prefer not to fluoridate. Another challenge encountered: some communities don’t drink their tap water. The taste, color, or odor may not be of their liking, or they feel the source of their water is corrupted (the lake looks dirty). There is a perception that bottled water is purer, healthier and safer and that is the preference for the family.

    All that being said, we continue promote CWF and remain hopeful. The article “Setting the Record Straight on Fluoride” is helpful!

    • Steve Slott said:

      FAN uses water treatment personnel as a back door to get to local City Councils and other decision makers. Such personnel who are vulnerable to FAN dogma will often go to their bosses and civic leaders with their “concerns” about fluoridation, and then simply recite the standard FAN misinformation. Enlightened civic leaders will usually not accord credence to these “concerns”, however, there are those who occassionally will begin discussions on fluoridation based on these concerns, and the floodgates of misinformation will then swing wide open.

      Here is information that AAP has on its website……. http://www.ilikemyteeth.org……in regard to cost savings, along with the references which are cited. I’ve also included some additional cost studies at the end of the AAP references.

      Savings from Water Fluoridation:
      What the Evidence Shows

      Research shows that community water fluoridation offers perhaps the greatest return-
      oninvestment of any public health strategy. The reduction in just the costs of filling and
      extracting diseased teeth and time lost from work to get care—not counting reduction in
      dental pain and discomfort—more than makes up for the cost of fluoridation. In recent
      decades, the evidence showing savings has grown:

      • For most cities, every $1 invested in water fluoridation saves $38 in dental
      treatment costs.1

      • A Texas study confirmed that the state saved $24 per child, per year in Medicaid
      expenditures for children because of the cavities that were prevented by drinking
      fluoridated water.2

      • A 2010 study in New York State found that Medicaid enrollees in less fluoridated
      counties needed 33 percent more fillings, root canals, and extractions than those
      in counties where fluoridated water was much more prevalent.
      treatment costs per Medicaid recipient were $23.65 higher for those living in less
      fluoridated counties.4

      • mResearchers estimated that in 2003 Colorado saved nearly $149 million in
      unnecessary treatment costs by fluoridating public water supplies—average
      savings of roughly $61 per person.5

      • A 1999 study compared Louisiana parishes (counties) that were fluoridated with
      those that were not. The study found that low-income children in communities
      without fluoridated water were three times more likely than those in communities
      with fluoridated water to need dental treatment in a hospital operating room.

      • By reducing the incidence of decay, fluoridation makes it less likely that
      toothaches or other serious dental problems will drive people to hospital
      emergency rooms (ERs)—where treatment costs are high. A 2010 survey of
      hospitals in Washington State found that dental disorders were the leading
      reason why uninsured patients visited ERs.7

      • Scientists who testified before Congress in 1995 estimated that national savings
      from water fluoridation totaled $3.84 billion each year.

      References

      1 “Cost Savings of Community Water Fluoridation,”
      U.S. Centers for Disease Control and
      Prevention, accessed on March 14, 2011 at
      http://www.cdc.gov/fluoridation/fact_sheets/cost.htm.

      2 “Water Fluoridation Costs in Texas: Texas Health Steps (EPSDT-Medicaid),
      Department of Oral Health Website (2000),
      http://www.dshs.state.tx.us/dental/pdf/fluoridation.pdf, accessed on August 1, 2010.

      3 Kumar J.V., Adekugbe O., Melnik T.A., “Geographic Variation in Medicaid Claims for
      Dental Procedures in New York State: Role of Fluoridation Under Contemporary
      Conditions,”
      Public Health Reports, (September-October 2010) Vol. 125, No. 5, 647-54.

      4 The original figure ($23.63) was corrected in a subsequent edition of this journal and
      clarified to be $23.65. See: “Letters to the Editor,”
      Public Health Reports (November-
      December 2010), Vol. 125, 788.

      5 O’Connell J.M. et al., “Costs and savings associated with community water fluoridation
      programs in Colorado,”
      Preventing Chronic Disease (November 2005), accessed on
      March 12, 2011 at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1459459/.

      6 “Water Fluoridation and Costs of Medicaid Treatment for Dental Decay – Louisiana,
      1995-1996,”
      Morbidity and Mortality Weekly Report, (U.S. Centers for Disease Control
      and Prevention), September 3, 1999, accessed on March 11, 2011 at
      http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4834a2.htm.

      7 Washington State Hospital Association, Emergency Room Use (October 2010) 8-12,
      http://www.wsha.org/files/127/ERreport.pdf, accessed February 8, 2011.

      8 Michael W. Easley, DDS, MP, “Perspectives on the Science Supporting Florida’s Public
      Health Policy for Community Water Fluoridation,”
      Florida Journal of Environmental
      Health, Vol. 191, Dec. 2005, accessed on March 16, 2011 at
      http://www.doh.state.fl.us/family/dental/perspectives.pdf.

      Additional:

      An economic evaluation of community water fluoridation.
      Griffin SO, Jones K, Tomar SL.
      Centers for Disease Control and Prevention, Division of Oral Health, Surveillance, Investigations and Research Branch, 4770 Buford Highway, MSF10, Chamblee, GA 30341, USA. sig1@cdc.gov
      J Public Health Dent. 2001 Spring;61(2):78-86.

      Water fluoridation could save NHS millions every year
      C Albert Yeung consultant in dental public health
      NHS Lanarkshire, Kirklands, Bothwell G71 8BB, UK
      BMJ 2014;348:g2855
      © BMJ Publishing Group Ltd 2014

      —–A Simulation Model for Designing Effective Interventions in Early Childhood Caries
      Gary B. Hirsch, SM; Burton L. Edelstein, DDS, MPH; Marcy Frosh, JD; Theresa Anselmo, MPH, BSDH, RDH 
      http://www.cdc.gov/pcd/issues/2012/11_0219.htm

      Steven D. Slott, DDS

  4. This is a useful summary about the state of fluoridation for the public. Thank you.

  5. This article recognizes Portland as the only large US city to not have optimal fluoridation. Let us not forget Honolulu, where there is a high rate of caries in children.

    • nyscof said:

      Actually, the Harvard researchers who produced the meta-analysis which concluded that fluoride is linked to lower IQ reported the link at levels the US EPA says is safe – less than 4 mg/l.

      · One study, sponsored by UNICEF, found reduced IQ at just 0.88 mg/l – a level within the “optimal” fluoride range added to the drinking water of over 200 million Americans.

      Seven found reduced IQs among children drinking water with fluoride levels between 2.1 and 4 mg/l — levels that 1.4 million Americans drink everyday.

      Four found effects at levels between 1.8 and 2.0 mg/l — levels that over 200,000 Americans drink everyday.

      Also, water fluoride levels do not equate to an individual’s daily fluoride dose from all sources – which should be the primary consideration.

      Studies showing fluoride can lower IQ are just the tip of the iceberg in fluoride/neurotoxicity research.

      Human research now shows that fluoride can damage the [link=http://fluoridealert.org/studies/brain05/]fetal brain[/link], adversely affect [link=http://www.fluoridealert.org/wp-content/uploads/li-2004.pdf]newborn babies'[/link] behavior, damage the central nervous system of [link=http://fluoridealert.org/wp-content/uploads/Yazdi-20111.pdf]fluoride-exposed workers[/link], and affect performance on [link=http://fluoridealert.org/studytracker/15086/]neurological assessment tests[/link]. And the IQ studies keep on coming. Forty one out of 48 studies show fluoride [link=http://fluoridealert.org/studies/brain01/]reduces IQ[/link]; 17 at levels the US EPA claims are safe.

      Over [link=http://fluoridealert.org/studytracker/?effect=brain-2&sub=cellulartissue-damage&type=animals&start_year=&end_year=&fulltext=&fantranslation=]100[/link] animal studies show fluoride can directly ddamage brain; with another [link=http://fluoridealert.org/studytracker/?effect=brain-2&sub=cognitive&type=animals&start_year=&end_year=&fulltext=&fantranslation=]30[/link] animal studies showing fluoride impairs learning or memory — including four published in 2014. In [link=http://www.ncbi.nlm.nih.gov/pubmed/24184405]one study[/link] published this year in the journal Physiology & Behavior, researchers found that fluoride “induces cognitive deficits and anxiety-depression-like behaviors in mice.” (Liu 2014)

      In the early 1990s, toxicologist [link=http://www.ncbi.nlm.nih.gov/pubmed/7760776]Dr. Phyllis Mullenix[/link] predicted that fluoride could cause “IQ deficits and/or learning disabilities in humans” based on the behavioral effects she observed in fluoride-exposed rats in her laboratory at the Harvard-affiliated Forsythe Institute in Cambridge, Massachusetts.

    • nyscof said:

      Long Island, New York (Nassau and Suffolk Counties) is totally non-fluoridated and its where 3 million people live. NYS Dept of Health Statistics show that Long Islanders enjoy a lower tooth decay rates than most of the more highly fluoridated counties in NYS. The two Long Island counties also have a lower rate of ER visits for toddler tooth decay. Dr. J. Kumar has recently admitted that disparities have increased between haves and have nots in New York – whether the water is fluoridated or not.

  6. Steve Slott said:

    Nyscof, here’s a novel idea…..how about if you provide valid cites to these “studies” you purport to support the ridiculous IQ reduction nonsense? Please cite their original sources such that they can be viewed in their entire and proper context. Citing your own “fluoridealert” is meaningless. The filtered and edited “information” posted on that, and any other little antifluoridationist website, is evidence of nothing other than the poor judgment of anyone who accords it any credibility.

    The Harvard study you reference was actually a review of 27 Chinese studies found in obscure Chinese scientific journals, of the effects of high levels of naturally occurring fluoride in the well water of various Chinese, Mongolian, and Iranian village. The concentration of fluoride in these studies was as high as 11.5 ppm. By the admission of the Harvard researchers, these studies had key information missing, used questionable methodologies, and had inadequate controls for confounding factors. These studies were so seriously flawed that the lead researchers, Anna Choi, and Phillippe Grandjean, were led to issue the following statement in September of 2012:

    “–These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S. On the other hand, neither can it be concluded that no risk is present. We therefore recommend further research to clarify what role fluoride exposure levels may play in possible adverse effects on brain development, so that future risk assessments can properly take into regard this possible hazard.”

    –Anna Choi, research scientist in the Department of Environmental Health at HSPH, lead author, and Philippe Grandjean, adjunct professor of environmental health at HSPH, senior author

    As it seems there have been no translations of these studies into English by any reliable, objective source, it is unclear as to whether they had even been peer-reviewed, a basic for credibility of any scientific study. These studies were flawed that nothing could be “concluded” from them.

    Steven D. Slott, DDS

  7. Steve Slott said:

    Nyscof, just to point out how absurdly flawed were those Chinese studies, the following is from the Harvard Meta-analysis:

    —-Developmental Fluoride Neurotoxicity: A Systematic
    Review and Meta-Analysis
    Anna L. Choi, Guifan Sun, Ying Zhang, Philippe Grandjean

    From page 4 Conclusion:

    “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.”

    Note: HIGH fluoride exposure. Water is fluoridated at 0.7 ppm, an extremely LOW concentration.

    Page 9

    “Six of the 34 studies identified were excluded due to missing information on the number of
    subjects or the mean and variance of the outcome (see Figure 1 for a study selection flow chart
    and Supplemental Material, Table S1 for additional information on studies that were excluded
    from the analysis). ”

    Page 13

    “Children who lived in areas with high fluoride exposure had lower IQ scores than those who lived in low exposure or control areas.”

    Once again, note: HIGH fluoride exposure. Water is fluoridated at 0.7 ppm, an extremely LOW concentration, exactly in the r.       ange of the control groups in this study.

    Page 13-14

    “While most reports were fairly brief and complete information on covariates was not available, the results tended to support the potential for fluoride-mediated developmental neurotoxicity at relatively high levels of exposure in some studies.”

    Incomplete information on covariates (controls). Relatively HIGH levels of fluoride. Water is fluoridated at 0.7 ppm, an extremely LOW concentration.

    Page 15

    “The present study cannot be used to derive an exposure limit, as the actual exposures of the
    individual children are not known. Misclassification of children in both high- and low-exposure
    groups may have occurred if the children were drinking water from other sources (e.g., at school
    or in the field).”

    Page 15-16

    “Still, each of the articles reviewed had deficiencies, in some cases rather serious, which
    limit the conclusions that can be drawn. However, most deficiencies relate to the reporting,
    where key information was missing. The fact that some aspects of the study were not reported
    limits the extent to which the available reports allow a firm conclusion. Some methodological
    limitations were also noted. Most studies were cross-sectional, but this study design would seem appropriate in a stable population where water supplies and fluoride concentrations have
    remained unchanged for many years. The current water-fluoride level likely also reflects past
    developmental exposures. In regard to the outcomes, the inverse association persisted between
    studies using different intelligence tests, although most studies did not report age adjustment of
    the cognitive test scores.”

    As I’ve said, the 27 Chinese studies were so flawed as to have no value, whatsoever, in evaluating water fluoridated at 0.7 ppm in the U.S.

    Steven D. Slott, DDS

    • nyscof said:

      The following is from Dr. Grandjean’s website

      Here is what the study showed: On average, the children with higher fluoride exposure showed poorer intelligence test performance. The high exposures generally exceeded the concentrations normally occurring in fluoridated drinking water, but only 4 of 27 studies reached an excess of 10-fold, and clear differences were found also at much lower exposures.

      Addition of fluoride to drinking water has been controversial since the very beginning in the 1940s. As noted in a National Research Council report, neither benefits nor risks have been thoroughly documented. Current dietary intakes of fluoride and dental hygiene practices differ from the circumstances first studied in the mid-20th century. By now, less than 6% of the world population receive what some dentists call “optimal” fluoride concentrations in drinking water, and safety concerns continue to linger.

      At the same time, many millions of people receive drinking water with fluoride concentrations that are clearly toxic. Benefits and risks, and their dependence on dose and individual susceptibility, need to be carefully evaluated, also in regard to alternative interventions, when relevant.

      Chemical brain drain should not be disregarded. The average IQ deficit in children exposed to increased levels of fluoride in drinking water was found to correspond to about 7 points – a sizable difference. To which extent this risk applies to fluoridation in Wichita or Portland or elsewhere is uncertain, but definitely deserves concern.

      http://braindrain.dk/2013/02/fluoridated-water-and-brains/

      • Steve Slott said:

        Nyscof

        Grandjean and Choi clearly spell out, in their review, the serious flaws in those Chinese studies, flaws which I have posted previously. Grandjean and Choi have also distanced themselves from these studies with their statement, found on the Harvard School of Public Health website, that the Chinese studies should not be used to assess fluoridated water in the US. If you have a problem with their findings then you should inquire of Grandjean if he and Choi would be willing to change their findings to better suit your personal ideology.

        Steven D.Slott, DDS

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