Dear CNN Editorial Team,
We are writing in response to your recent article "Children exposed to higher fluoride levels have lower IQs, a government study finds" (January 6, 2025). While we appreciate your coverage of this important public health topic, we must express serious concerns about the article's framing and significant omissions that could mislead your readers about water fluoridation – one of public health's most successful interventions.
Your Headline Requires Critical Context
Your headline and opening paragraphs lack essential context about the National Toxicology Program (NTP) study's actual implications. Specifically, the research examined fluoride levels of ≥1.5 mg/L – more than double the amount (0.7 mg/L) used in U.S. community water fluoridation programs. This distinction is paramount, yet it appears only deep within the article. The NTP highlights that the current amount of fluoride recommended in U.S. community water supplies has not been demonstrated to have a negative effect on children’s IQ.
Moreover, when you report that "every 1 part per million increase in fluoride in urine... was associated with a roughly 1 point drop in a child's IQ score," you don't emphasize that this finding pertains to exposure levels far above what the vast majority of Americans encounter. Only about 0.6% of the U.S. population (approximately 1.9 million people) are exposed to these naturally high fluoride levels that were the focus of the study. And even this small subgroup of Americans has protections in place from the Safe Drinking Water Act, which ensures that anyone with fluoride concentration greater than 2.0 mg/mL be notified by their public water system.
Your article accepts without question that IQ scores provide a reliable measure of cognitive ability. However, the scientific community has long debated the validity and reliability of IQ testing, particularly in children. IQ scores can be influenced by numerous factors including testing conditions, cultural context, socioeconomic status, and even the time of day. Moreover, a one-point difference in IQ score - the magnitude of change your article highlights - falls well within the standard error of measurement for most IQ tests and is highly unlikely to translate to any meaningful difference in real-world cognitive function or life outcomes.
When discussing potential cognitive impacts, it's essential to distinguish between statistical significance and clinical significance. While researchers may detect small statistical differences in large population studies, this doesn't necessarily indicate meaningful impacts on individual children's cognitive development or functioning. Your article's emphasis on a one-point IQ difference risks causing unnecessary alarm about an effect that may have no practical significance.
Your article would benefit from acknowledging the significant scrutiny the NTP report has faced. The American Dental Association (ADA) has highlighted several methodological concerns, including:
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Inconsistent application of risk of bias criteria
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Inadequate statistical rigor
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Selective reporting of non-significant study results
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Most studies were conducted outside the U.S. in areas with naturally high fluoride levels
Earlier drafts of this report required major revision after peer review by the National Academies of Sciences, Engineering and Medicine found they "would not survive scientific scrutiny." While the final version has been improved, many of these fundamental concerns persist.
The authors of the JAMA paper themselves even note as a limitation that “many of the studies (included in the meta-analysis) were classified as having a high risk of bias.”
The Overlooked Health Impacts of Poor Dental Care
Your article focuses exclusively on theoretical risks while ignoring the well-documented cognitive and health impacts of poor dental hygiene. Research has demonstrated clear links between oral health and overall well-being, including cognitive function. Untreated dental problems can lead to chronic inflammation, which is associated with cognitive decline. Moreover, children with poor dental health often face challenges in school due to pain, difficulty eating, sleep disruption, and decreased self-esteem - all factors that can impact learning and cognitive development.
The historical record is clear: before widespread fluoridation, dental infections were a leading cause of death. While such severe outcomes are rare today thanks to modern dental care and fluoridation, we still see significant impacts of poor dental health, including:
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Chronic pain affecting concentration and learning
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Systemic inflammation linked to cognitive impairment
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Nutritional deficiencies from difficulty eating
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Sleep disruption affecting memory and attention
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Social and psychological impacts affecting academic performance
These documented impacts on cognition and health deserve consideration alongside any discussion of fluoride safety.
The Missing Health Equity Story
Perhaps most concerning is your article's near-complete omission of the significant health equity implications of water fluoridation. As public health scientists and practitioners, we believe your readers deserve to understand that:
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Water fluoridation prevents at least 25% of tooth decay in children and adults
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Every $1 spent on fluoridation saves approximately $20 in dental procedures
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The impact is most pronounced in lower-income communities where access to regular dental care may be limited
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Fluoridation provides universal protection regardless of socioeconomic status or access to dental care
The experience of cities that have ceased fluoridation is instructive. In Calgary, which ended fluoridation in 2011, researchers documented increased social inequities in dental health. Similarly, after Juneau, Alaska removed fluoride in 2007, there were significant increases in dental procedures related to cavities, with the impact falling disproportionately on children from socioeconomically disadvantaged families.
Historical Context Matters
Your readers would benefit from understanding why water fluoridation was implemented in the first place. In the early 1900s, dental infections were a major cause of mortality. The discovery that fluoride could prevent tooth decay led to one of public health's greatest achievements. In Grand Rapids, Michigan – the first city to fluoridate its water – researchers documented a 60-65% reduction in dental caries among children who consumed fluoridated water from birth.
Recommendations for Future Coverage
As a trusted news source, CNN has a responsibility to provide comprehensive, contextualized coverage of public health issues. Future reporting on this topic should:
1. Clearly distinguish between exposure levels in research studies and those used in U.S. water fluoridation programs
2. Include context about the proportion of the population affected by high natural fluoride levels
3. Address the health equity implications of water fluoridation
4. Consider the comprehensive body of evidence supporting fluoridation's safety and effectiveness
5. Consult a broader range of experts, including public health practitioners and health equity researchers
Consensus Matters
The scientific consensus remains clear: community water fluoridation at recommended levels (0.7 mg/L) is safe and effective. Major health organizations worldwide, including the World Health Organization, American Dental Association, and Centers for Disease Control and Prevention, continue to endorse this practice.
While ongoing scientific inquiry into fluoride's effects is important, it's essential that media coverage provides proper context and avoids sensationalism that could undermine public health. This one new review does not actually add much to our understanding of fluoride. The real story here isn't about the dangers of water fluoridation – it's about the importance of maintaining appropriate safety margins while preserving one of public health's most successful and equitable interventions.
We urge you to consider publishing a follow-up piece that addresses these essential missing elements and provides your readers with the full context they need to understand this important public health issue.
Sincerely,
Dr. Jess Steier, DrPH, Public Health Scientist, Founder of Unbiased Science
Dr. Joe Schwarcz, PhD, CM, Chemist, Director of McGill University’s Office for Science & Society
Dr. Katrine Wallace, PhD, Epidemiologist, University of Illinois Chicago School of Public Health
Dr. Ashley Lerman, DDS, Diplomate, American Board of Pediatric Dentistry, Columbia University College of Dental Medicine
Dr. Norbert Kaminski, PhD, Immunotoxicologist, Director of the Institute for Integrative Toxicology, Michigan State University.
Dr. Ryan Marino, MD, Medical Toxicologist & Associate Professor Case Western Reserve University School of Medicine
Michelle Bridenbaker, RN, BSN, MS, MBA, Critical Care Nurse and Toxicologist
Dr. Sarah Scheinman, PhD, Neurobiologist, Northwestern University Feinberg School of Medicine
Dr. Nicole Lippman, Ph.D., Licensed Clinical Psychologist
Dr. Leigh Baxt, PhD, Drug Discovery Biologist
Dr. David Robert Grimes (PhD CStat), Trinity College Dublin School of Medicine
Dr. Shoshana Ungerleider, MD, Internal Medicine, Host/Producer TED Health
Whitney DiFoggio, MA, RDH, Registered Dental Hygienist and Doctoral Candidate at Eastern Virginia Medical School
Dr. Kevin C. Klatt, PhD, RD, Research Scientist, University of California Berkeley, Department of Nutritional Sciences & Toxicology
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As a diverse team of public health scientists, toxicologists, clinicians, chemists, epidemiologists, biologists, statisticians, and psychologists, we felt compelled to respond to CNN's recent coverage of fluoride safety. While we appreciate CNN's attention to public health topics, their January 6th article about fluoride exposure and IQ scores requires important scientific context and clarification. Though we note that CNN's accompanying video provides some additional context, research shows that many readers do not engage with supplementary content and primarily absorb information from headlines and article text alone. Our collective expertise across toxicology, neuroscience, epidemiology, clinical practice, and public health policy positions us to address several critical omissions in the reporting that could unnecessarily alarm the public about one of our most successful public health interventions.
Unbiased Science combats health & science mis- and dis-information. Contact us at jsteier@unbiasedscipod.com.
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