A closer look at fluoridation
- Published: November 18, 2010
At a Village Council-sponsored forum on fluoridated water last weekend, some lesser known facts were shared by several scientists who were invited to speak on the sometimes controversial issue. While ingesting fluoride is not recommended for infants, for example, children between the ages of 1 and 5 who are exposed to fluoride show a greater resistance to dental caries. But whether it’s about the benefits or the dangers of fluoridated water, most of the studies conducted around the world over the past 50 years on the subject have produced inconclusive results.
About 30 villagers attended Saturday’s fluoridation forum held in the Bryan Center gym and moderated by local resident Meg Carver. Kevin Schlueter, a biochemist at YSI, Inc. made the case for fluoride, while Kathleen Thiessen, a senior scientist with SENES Center for Risk Analysis in Oak Ridge, Tenn., presented data on the risks of fluoridation. Local resident Mary White, professor of medical ethics at Wright State University School of Medicine, also spoke about issues to consider when evaluating data and considering matters of public health.
Participants displayed a high level of civility and respect during the event, including the period devoted to questions and answers. After hearing both sides, Village engineering consultant and local resident John Eastman suggested that the Village pursue a compromise by using the natural level of fluoride in the village water, .4 mg/liter, and adding .6 mg/liter to get a level of 1 mg/liter, which is the middle of the current range between .8 and 1.3 mg/liter. Another participant suggested raising the level of fluoride to the lower recommended limit of .7 mg/liter. But Council had designated the event as information gathering only, and most participants held their involvement to questions.
Local resident Hap Cawood, who attended the forum, saw the complications involved with finding reliable evidence and left without a definitive opinion. He summarized his position thus:
“I can now understand Franklin D. Roosevelt’s way of making decisions in the upheaval of the Depression; he agreed with the expert he heard last.”
Last year Village Environmental Commission analyzed the benefits and risks of fluoridated water and recommended to Council last spring that the Village stop fluoridating its water supply, a practice the Village has continued since 1959. Council has researched and discussed the issue since last spring, and has not yet announced when a decision might be made.
Schlueter began by stressing that while ingesting high levels of fluoride can be toxic, the levels that the Centers for Disease Control recommend for drinking water, between .7–1.2 mg/liter, are considered safe for most people.
Infants who ingest large amounts of fluoride can develop varying degrees of dental or skeletal fluorosis (a disease that discolors and in some cases damages bones and teeth), Schlueter said, referring especially to babies who drink formula with fluoridated water. But other studies that claim that fluoride can cause problems with the pituitary gland, the thyroid or goiter, for instance, don’t show epidemiological evidence that identifies fluoride as the defacto cause of these health problems, Schlueter said.
In favor of fluoride, Schlueter finds sound evidence which shows that populations that don’t fluoridate their water have a higher incidence of cavities in children, he said. Fluoride exposure for children between the ages of 1 and 5 whose teeth are still forming develop stronger teeth and therefore a greater resistance to cavities.
And in the end, the cost of fluoridation is pennies per week, compared to the expensive cavity fillings those who didn’t get fluoride might face, meaning in Schlueter’s mind, “the risks [of fluoridating] are far outweighed by the benefits.”
Presenting an argument to the contrary, Theissen came armed with reams of data, graphs and charts that for her answer two key questions: Is fluoride beneficial to the community? Is it safe for the community? Her first of many data sets showed that fluoride intake varies widely between individuals due to the variable amount of water they drink on a daily basis, which can vary by a factor of 100 mg/kilogram of body weight when comparing, for instance, an athlete to a senior citizen. Higher rates of water intake increase the levels of fluoride intake beyond optimal levels of consumption, which are between .05–.07 mg/kilogram/day. Babies who drink formula with fluoridated water, for instance, can ingest as much as .15 mg/kg per day, Theissen said.
The benefits of fluoride aren’t as clear as they were once thought, according to Theissen, who presented a study showing that the cavity rate in fluoridated areas decreased by 18 percent, which Theissen equated to “half of one tooth surface.” And for a host of reasons, cavity rates of people all over the world, regardless of their exposure to fluoridated water, have steadily declined over the past 50 years.
On the questions of ethics, White offered some criteria for how to evaluate the effects of fluoride and ultimately how to decide whether to add it to the local water supply. She focused first on a comprehensive review published in 2000 in a British medical journal analyzing the widest number of studies worldwide ever published on the effects of fluoride. The review’s conclusion about the entire body of evidence was that “the quality of the studies was uniformly weak” and contained “a lack of use of contemporary methodologies and a poor analysis of variables,” White reported.
Still, the review looked at the highest level studies and found consistent evidence that fluoride does reduce the incidence of dental caries, that fluorosis is a mild risk, that fluoride may actually benefit skeletal development, and that there appeared to be a benefit over time for adults and for racial minorities.
“I was surprised by the level of uncertainty,” White said of her reaction to the findings.
White cautioned community members about the risk of making decisions under conditions of disagreement.
“Clearly there is a great deal of uncertainty in the community [on fluoridation], and decisions made under these conditions are vulnerable to error,” she said.
In making decisions about public health policy, White said, the community is ethically obligated to consider its responsibility to remove harms, ensure that the benefits and risks are equitably distributed within the community, encourage public participation and balance the benefits against the burdens.