Fluoride-free water may lead to decay— Study looks at defluoridation
- Published: October 31, 2013
Local children have higher rates of tooth decay than their older peers, who have had access to fluoridated water for a longer period of time, according to the preliminary results of a Greene County Combined Health District surveillance study.
The study looked at the teeth of 24 local third and eighth graders two years after the Village stopped adding fluoride to municipal water. The Village ceased the practice in 2011.
The study also showed that children under 12 who used extraneous fluoride, such as fluoride rinses, drops or tablets, had, on average, almost three fewer dental cavities than those who did not.
Dr. Don Brannen, an epidemiologist with the health district, said that the results are only preliminary, as he hopes the study is continued for many years, but that initial observations were so remarkable the study group urged the County Health Commissioner to make them public.
“Even though the numbers are small, rarely do you in public health have something that is such an obvious dose response curve,” Brannen said. “The students who had less exposure to fluoridated water had greater amounts of caries (cavities) in that short amount of time.”
But according to Vickie Hennessy of Green Environmental Coalition, who had previously urged the Village to stop adding fluoride, the study is both flawed and biased.
“Not only is it biased by the team, it does not follow scientific method at all,” Hennessy wrote in an email. “There is no mention of the methods used to select the subjects and no explanation at all of the data collection or statistical analysis.”
Because the health district publicly advocates for municipal water fluoridation, it isn’t the best group to undertake such a study, Hennessy added.
In February 2011 Council voted to discontinue the practice of adding fluoride to municipal water, which the Village had done for more than 50 years. After Council’s decision, retired local physician Dr. Carl Hyde, an advocate for fluoridation, remained concerned that the teeth of local children would suffer, and asked the health district to launch a study. The health district had already known that U.S. Public Health Service recommends longitudinal, or long-term, studies in communities that decide not to add fluoride to their water, according to Brannen.
The study, “A Community Based Response to Municipal Water Defluoridation,” included a dental screening of 24 children during school by a registered dental hygienist over two days in December 2012 and January 2013. The parents or guardians of less than half of those students also filled out an online survey, or exposure assessment, of their children’s oral care and drinking water habits. A total of 641 teeth were examined.
Participation in the study was admittedly low, but enough children took part in the study to show how effective fluoride is at preventing cavities, Brannen said. Just three children over 12 were screened, but that was enough to conclude: “When both permanent (adult) and deciduous (child) tooth decay were examined the younger children (without access to municipally fluoridated water sources) had significantly higher tooth decade than those who did have access.”
According to Brannen, the health district does hope to study a larger number of children over a longer period of time in order to evaluate the long-term effects of de-fluoridated water. The goal is for every parent or guardian to complete a survey with at least half of all children in Yellow Springs consenting to a free dental screening. (There were 688 children here in the 2010 census). If the Greene County Health Commissioner, Yellow Springs schools and the Yellow Springs Village Council agree, the health district would perform both the survey and screening once each school year, Brannen added.
“Eventually we would go back in 10 and 20 years to see if the results were the same,” Brannen said. “I would like to see this because Yellow Springs is such a socially-conscious area and potentially with a long-term study we could know whether the amounts of fluoride are right or wrong.”
In a separate 2009 analysis of county mortality rates over a 16-year period, the health district noted an increase in bone-related cancers and an “overwhelming number of dental caries in persons from the non-fluoridated areas” of the county, according to the report. Bone cancers occurred in 2.9 per 10,000 persons in non-fluoridated areas rather than 2.1 per 10,000 persons in fluoridated areas, which is “unusually high,” Brannen said. The results were surprising as some anti-fluoride activists have linked fluoride to an increase in bone cancer, Brannen said.
Other authors credited on the study were Hyde, Dr. Dean Olson, director of the Aerospace Medicine Residency Program at Wright State University’s Boonshoft School of Medicine, Roopsi Narayan from the Department of Community Health at Wright State, Janice Gray and Robyn Fosnaugh of the Greene County Combined Health District and County Health Commissioner Melissa Howell.
While Hennessy at one time suggested that Council consider an objective third party group to conduct a fluoride study, now she believes a study is not needed. That’s because the difference is now so small between the amount of fluoride present naturally in Village water and the new recommended amount (updated later in 2011) from the U.S. Department of Health and Human Services and the U.S. Environmental Protection Agency. The Village had been adding enough fluoride to bring the concentration up from the naturally occurring fluoride level of 0.4 milligrams per liter to 1.0 mg/L, which was within federal recommendations at the time of 0.7 mg/L to 1.2 mg/L. The new recommendation is now to add only enough fluoride to bring the water to 0.7 mg/L.
“It also occurs to me what a small amount of fluoride we’re talking about at this point,” Hennessy wrote of the difference, just 0.3 mg/L. “It just doesn’t seem worth quibbling about.”
Hennessy reaffirmed her conviction, based upon various studies, that fluoride works to reduce tooth decay when it is used topically and not by swallowing, while swallowing it remains a threat to health.
“Forcing people to ingest fluoride in their water source is an unjust and dangerous practice,” Hennessy wrote in her email. “It leads to many other detrimental health effects, and dental disease can be avoided by proper nutrition and good dental hygiene (brushing with fluoride toothpaste).”
Olson of Wright State, who modeled the survey used on a U.S. Centers for Disease Control template, said that while the study is preliminary, the results are already “powerful” in supporting other studies that show that fluoridation of public water is beneficial to dental health. He maintains that even though there was a small sample size, the results are mathematically significant and statistically sound.
Hyde hopes that the Village reverses its earlier decision and begins adding fluoride again. Short of that action, local physicians and pediatricians in the village can promote fluoride drops and other supplements, which can help prevent tooth decay, even though it’s not as good as having it in drinking water, he said. Hyde remains convinced of the effectiveness of fluoridated public water.
“Having fluoridated water makes a lot of difference, lifelong, to have good teeth, not only in quality of life but expense,” Hyde said.
Brannen said that the results come with a caveat. They are tentative, in small numbers and since there were so few returned exposure assessment surveys, the group had to use age as a surrogate for fluoride exposure (under the assumption that those who are older had more access to municipal water). More participation is needed if the study is going to continue, Brannen said. The “lackluster” response to this first round may have been because of a perception that the health district is biased, which Brannen says is not the case.
“On this project, we wanted to stop being a public health advocate and start being an advocate for unbiased research,” he said.
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