Re: “Ending fluoridation was a rotten idea,” Rob Breakenridge, Opinion, May 22.
The column by Rob Breakenridge on fluoridation is misleading on several points. Presumably the column is a reaction to the current flurry over the suggestion by two dentists that city council consider reintroducing fluoridation.
The decision to stop fluoridation was made after long consideration by members of council who had been in office for multiple terms. Twelve of the 15 members voted to stop fluoridation. Ald. Gord Lowe, a longtime supporter, voted to continue it. The remaining two who voted to continue, being new to the issue, had pleaded lack of knowledge and chose the status quo.
In his column, Breakenridge expresses puzzlement over what benefits council expected of its decision. I can’t speak for councillors, but from my experience with that process, I suggest that those who voted to stop fluoridation expected fewer adverse effects associated with swallowing fluoride and other products of hydrofluorosilicic acid (the industrial grade chemical that was used to fluoridate Calgary’s water). And I suppose they would expect the certainty that the residents of Calgary would have a significant control over their own medication, a control denied by fluoridation, and a matter of medical ethics and human rights.
Now council is urged by two Calgary dentists to reconsider. They claim that the prevalence of cavities in Calgary has increased since fluoridation was stopped. According to the dental officer of health of Alberta Health Services stationed in Calgary, there is no systematically gathered data on the prevalence of cavities since cessation of fluoridation. So we are left to weigh the purported findings or impressions of two dentists taken from their personal practices against the systematic collections of data from millions of patients. That more abundant and more systematically gathered data indicate no substantial prevention of cavities by fluoridated water and no increase in the incidence of cavities after stopping fluoridation, as determined by comparison of cities stopping it with cities continuing it.
There are dozens of such studies. They show either no difference with the control cities, or show improvement of dental health after stopping. I am referring to actual scientific research published in credible journals, not to endorsements by various societies and government departments.
In his column, Breakenridge refers to citation of evidence by Alberta Health Services that supports the notion that fluoridation prevents cavities. There is no study that shows such effectiveness. Admittedly, it is claimed by AHS that there are such studies, but examination of these cited studies reveals them to be uncertain or contrary to their findings. I have witnessed this in AHS presentations before several town and city councils, including the hearings of Calgary city council and committees.
The claim of safety is also erroneous. The most comprehensive evaluation of the scientific literature on possible adverse effects was done by a panel of 12 scientists for the National Research Council of the United States and reported in 2006. It found association of using water containing fluoride — water with various concentrations of fluoride, including concentrations comparable to those in fluoridated tap water — with several abnormalities.
Those abnormalities included thyroid disease, dental fluorosis and hip fracture, among others. And they found probable adverse effects not proven, but certainly indicating that further research is needed.
The degree of certainty of adverse effects depends on what groups within the population are considered. Groups more susceptible to particular effects include infants, diabetics, persons with kidney disease and the elderly. These groups constitute sizable fractions of a population of 1.3 million. The failure of fluoridation of tap water to control the dose a person gets, and the fact that fluoride is accumulated in several tissues throughout life in a fluoridated city, are also major problems.
Breakenridge cites the Centers for Disease Control and Prevention and its dated overstatement on fluoridation. But the CDC, as of 1999, along with the American Dental Association, agree with research that seems to show a slight benefit in preventing cavities from topical application of fluoride directly to the tooth enamel rather than from a systemic effect.
So why risk harms, some of which are certain to occur, when swallowing fluoride is essentially ineffective and there are alternative measures that do seem to prevent cavities such as a good diet and consistent dental hygiene?
James S. Beck, MD, PhD, is professor emeritus of medical biophysics at the University of Calgary and co-author of a 2010 book on fluoridation.