Fluoride Action Network

Green 2019 Study: Second U.S. Government Funded Study Shows Low Fluoride Exposure Reduces IQ

Fluoride Action Network | August 19, 2019


The world’s premier pediatric journal has published a new government-funded study confirming our worst fears, linking exposure to “optimally” fluoridated water during pregnancy to lowered IQ for the child.

Above Video: Game-Changing Fluoride Neurotoxicity Study #2: Green 2019 

You can repair a cavity, but you cannot repair a child’s brain.

The American Medical Association’s journal on pediatrics (JAMA Pediatrics) has published the second U.S. Government-funded study linking low-levels of fluoride exposure during fetal development to cognitive impairment.  The observational study, entitled Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada, was led by a team at York University in Ontario, Canada and looked at 512 mother-child pairs from six major Canadian cities.  It was funded by the Canadian government and the U.S. National Institute of Environmental Health Science. 

The scientists assessed fluoride exposure two ways. They measured fluoride in women’s urine samples during pregnancy. They also calculated fluoride consumption based on how much is in a city’s water supply and how much women recalled drinking. They found that a 1 mg per liter increase in concentration of fluoride in mothers’ urine was associated with a 4.5 point decrease in IQ among boys, though not girls. When the researchers measured fluoride exposure by examining the women’s fluid intake, they found lower IQs in both boys and girls: A 1 mg increase per day was associated with a 3.7-point IQ deficit among both genders.

Above Video: Paul Connett Responds to Criticisms of the JAMA Fluoride IQ Study


Making the publication of this study even more impactful is that it is accompanied by an editor’s note, a podcast featuring the journal’s editors, and an editorial from world-renowned neurotoxicity expert Dr. David Bellinger.  This reaction by the JAMA editors shows just how important the study is, as most studies in their journal don’t receive this treatment.

For the first time in his career, the editor of Pediatrics included an editorial note, knowing fluoridation proponents would attack the study without justification. He noted the study’s rigor, triple-checking of the data, and definitive nature of the evidence:

This decision to publish this article was not easy. Given the nature of the findings and their potential implications, we subjected it to additional scrutiny for its methods and the presentation of its findings. The mission of the journal is to ensure that child health is optimized by bringing the best available evidence to the fore. Publishing it serves as testament to the fact that JAMA Pediatrics is committed to disseminating the best science based entirely on the rigor of the methods and the soundness of the hypotheses tested, regardless of how contentious the results may be. That said, scientific inquiry is an iterative process. It is rare that a single study provides definitive evidence. This study is neither the first, nor will it be the last, to test the association between prenatal fluoride exposure and cognitive development. We hope that purveyors and consumers of these findings are mindful of that as the implications of this study are debated in the public arena.

A must-hear twelve-minute podcast (above) featuring AMA Pediatrics Editor in Chief, Dimitri Christakis, MD, MPH, and Frederick Rivara, MD, MPH, Editor in Chief of JAMA Network Open, was also released alongside the study.  The editors express how “very concerning” and “startling” the evidence is against fluoridation, and how the neurological damage is “on par with lead.”  They praise the high quality of this study, and call for additional NIH funding of more fluoride research.  Before publication, the study was subjected to two statistical reviews, with the researchers combing through the data to make sure that the results were not skewed by the mothers’ education, income levels, or other factors.

Most importantly, they recommend that pregnant women avoid drinking fluoridated water, something FAN has been saying since the publication of the Bashash et al, study two years ago.

“The effects of this study are comparable to the effects of lead, and if these findings are true there should be as much concern about prenatal fluoride exposure,” Christakis told The Daily Beast.  “The question that needs to be asked to every pediatrician, scientist, and epidemiologist is what they’re going to tell pregnant women,” said Christakis, who says he will advise his pregnant friends and family to avoid fluoridated water.  “We can’t tell them to wait years for another study.”

In the editorial piece by Harvard Professor Dr. David Bellinger that accompanies the study he provides an overview of recent fluoride/IQ research, and highlights the strengths of the study and need for additional research.  Though he also gives the following warning:

The hypothesis that fluoride is a neurodevelopmental toxicant must now be given serious consideration…It is instructive to recall that the hypothesis that subclinical lead exposures pose a neurodevelopmental hazard was bitterly contested in the 1980s and 1990s, and it was only the weight of evidence that eventually accumulated that led to the now widely held consensus that no level of lead exposure is safe…If the hypothesis is true, the implications are worrisome. Exposure to fluoride has increased substantially in recent decades…If the effect sizes reported by Green et al and others are valid, the total cognitive loss at the population level that might be associated with children’s prenatal exposure to fluoride could be substantial.

Keep in mind that this study does not stand alone.  Instead, it confirms previous findings by Bashash et al. in 2017 and Thomas et al. in 2018 that low levels of fluoride during fetal development will cause cognitive impairment, as well as over 300 animal and other human studies indicating fluoride’s potential to damage the brain.

Bashash in 2017 addressed virtually all the criticisms of the many papers published previously from China. This new study (Green et al 2019) addresses all of the minor criticisms of the Bashash study. Pro-fluoridation commentators said they wanted the Bashash study reproduced – this study does that. They also said they wanted to see a study in a North American population – this study does that.

In fact, this study goes beyond Bashash because they included measures of total dose of fluoride in addition to a measurement of the mothers’ urine levels.

There has already been widespread media coverage of this research. We will continue to update this page, as well as provide updates on our social media pages and with bulletins over the coming days.

See also quotes comparing the toxicity of fluoride to lead


News Coverage:

Reuters: https://in.reuters.com/article/us-health-pregnancy-fluoride/study-prompts-call-for-lower-fluoride-consumption-by-pregnant-women-idINKCN1V91C5

CNN: https://www.cnn.com/2019/08/19/health/fluoride-neurotoxin-canada-study/index.html

NPR: https://www.npr.org/sections/health-shots/2019/08/19/752376080/can-maternal-fluoride-consumption-during-pregnancy-lower-childrens-intelligence

Washington Post: https://www.washingtonpost.com/science/2019/08/19/study-raises-questions-about-fluoride-childrens-iq/

Time Magazine: https://time.com/5656476/is-fluoride-in-water-safe/

Yahoo News: https://news.yahoo.com/controversial-study-links-fluoride-water-lower-iq-162835811.html

WebMD: https://www.webmd.com/baby/news/20190819/could-fluoride-be-bad-for-baby-during-pregnancy

Daily Beast: https://www.thedailybeast.com/fluoridated-water-during-pregnancy-linked-to-lower-iqs-study-published-by-jama-pediatrics-says

Science Mag: https://www.sciencemag.org/news/2019/08/drinking-fluoridated-water-during-pregnancy-may-lower-iq-sons-controversial-study-says

CTV News: https://www.ctvnews.ca/health/higher-fluoride-levels-during-pregnancy-may-be-linked-with-lower-iq-scores-in-kids-study-1.4555550

Daily Mail: https://www.dailymail.co.uk/health/article-7371651/Pregnant-women-drink-fluoride-treated-water-children-lower-IQs-study-suggests.html

Newsmax: https://www.newsmax.com/health/health-news/study-fluoride-pregnant-women/2019/08/19/id/929045/

Globe and Mail: https://www.theglobeandmail.com/canada/article-experts-challenge-study-suggesting-children-exposed-to-higher-levels/

FOX News: https://fox4kc.com/2019/08/19/new-study-raises-questions-about-how-fluoride-affects-childrens-development/

Inquirer: https://www.inquirer.com/health/fluoride-water-safety-babies-brain-neurotoxin-cdc-20190819.html