As an emergency physician at Miles Memorial Hospital and former head of clinical research at a Cambridge, Mass. teaching hospital, I hope to provide some insight into the debate on Damariscotta’s water fluoridation, an issue set for a town vote on Nov. 8.
Subjectively, there is little doubt that dental health is of great importance to our community. Sadly, despite living in a modern era, I see nearly as many patients in Damariscotta with horrific teeth as I did while working in rural Africa in regions where no one received dental care. Remarkably, most of the dental cases I see now – not as a dentist but as an emergency physician – involve both severe decay and youthful patients.
Simply put, this combination should not be found in the developed world.
There’s no question that any public health intervention proven to improve dental health is a good thing. Thus, the debate turns on whether or not fluoridation of public drinking water is a proven intervention.
Because the medical literature is voluminous and requires a sophisticated understanding of statistical analysis, finding unbiased high-quality studies on water fluoridation is not a straightforward task.
Based on my experience teaching medical statistics, conducting and reviewing medical studies, and as someone with no stake in the Damariscotta water fluoridation issue, I can offer the following objective perspective on the question: will continued fluoridation of the town water help or harm its residents?
This perspective is based on a kind of medical research called the “systematic review.” Done properly, a systematic review serves as a sort of medical super study, where all prior research relevant to a subject is re-analyzed for quality, appropriate results combined, and the evidence reported in aggregate. In effect, systematic reviews weigh all existing research to provide a bottom line summary of what is known. This improves the quality of information used for decision making.
Since individual studies vary greatly in quality, methodology, size, and result, looking at one study at a time can be like the blind men who feel trunk, hooves, and tail but miss the elephant. What’s important is whether the combined weight of all existing studies (accounting for all of these individual study variations) supports or disproves a particular treatment.
With this background, the latest systematic review for water fluoridation was published by the British Medical Journal in 2000. It came from a British government research consortium with no financial ties to fluoridation efforts. (A free on-line link to it is provided at http://sn.im/fluoride.)
This review reported no link between fluoridation and serious harmful effects. Specifically, it found no association between fluoridation and any form of cancer or increase in bone fracture rates, issues historically raised by the lay press.
The review did find an association between fluoridation and tooth coloration, measurable in the number of additional people who got any amount of dental fluorosis, a condition where teeth develop small white streaks.
The review further noted a consistent association between water fluoridation and cavity reduction, measurable in the number of additional people who were completely cavity-free when compared to others who drank non-fluoridated water.
Thus, based on all the studies of drinking water fluoridation through 2000, fluoridating Damariscotta’s water should be expected to add one in six town water drinkers to the no-cavity population. (This doesn’t count people with cavities already who are protected from getting more.)
On the down side, it should also be expected to cause white streaks on the teeth of one in six town water drinkers.
I spend many hours making treatment decisions in the emergency room with less persuasive evidence. In my own opinion, a bit of fluorosis is a small price to pay for a proven intervention against cavities that requires no extra action on the part of the community.
If I had a treatment for patients suffering from tooth pain that made a difference for even one in a hundred patients, I’d most likely provide it. One in six? That’s pretty much a slam dunk.
Finally, prior criticism about Damariscotta’s fluoridation program has focused on the quality of fluoride used to supplement the water supply, specifically raising questions about possible water contamination with arsenic and mercury as well as uncontrolled concentrations of fluoride.
Damariscotta residents should know that their water supply must be tested several times a year to meet state safety standards. Testing reports are in the public domain. I obtained and reviewed the tests from 1999 to the present and was reassured by the results.
Since 1999, no arsenic or mercury has ever been detected in the town drinking water. During this same period, Damariscotta’s fluoride concentrations have ranged from 0.6 to 1.7 parts per million (ppm). The latest measurements, taken March 14 and Aug. 22, 2011, both returned concentrations of 0.7 ppm.
Given the U.S. standard range is 0.7 to 1.2, these results provide good evidence that the fluoride source is an acceptable one.
I hope this helps inform the debate.
(James Li, MD is an emergency room physician for Lincoln Medical Partners.)
