It has been called one of the 10 great public health achievements of the 20th century, yet 70 years after its introduction in the U.S., 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.
Richard Valachovic, DMD, MPH, president and CEO of the American Dental Education Association.Just this past summer, Israel's Minister of Health 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 U.S. Centers for Disease Control and Prevention (CDC).
Fluoridation opponents and studies
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 Environmental Health Perspectives (July 20, 2012) 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 pointed out, the exposed groups in the studies they reviewed had access to drinking water with fluoride concentrations up to 11.5 mg/L, so, in many cases, fluoride concentrations exceeded the levels recommended in the U.S. for improving oral health (0.7-1.2 mg/L) or allowed by the Environmental Protection Agency (4.0 mg/L.
Nevertheless, antifluoridation 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, DMD, MD, and the dean of the Faculty of Medicine at the Harvard Medical School, Jeffrey Flier, MD, 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.
Set the record straight
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 (Summer 2014) 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 the statement: "Public water fluoridation is really just a secret way for chemical companies to dump the dangerous byproducts of phosphate mines into the environment" (JAMA Int Med, May 2014, Vol. 174:5, pp. 817-818).
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.
Reliable sources of information
The CDC is an excellent place to start. The agency's "Community Water Fluoridation" frequently asked questions explain how fluoride works when added to drinking water and topical products such as toothpaste, and discusses the potential adverse effects from overexposure in clear and unbiased terms. Another U.S. 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 and also 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 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."
Impact and effects
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, healthcare providers, and school-age children about oral health.
These types of efforts are all 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."
Educate and lead the way
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, OR, 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.
The American Dental Education Association (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.
Richard Valachovic, DMD, MPH, is the president and CEO of the American Dental Education Association.
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