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In 1964, when I was a medical student, Birmingham City Council decided to fluoridate its water supply. Over the weekend that the fluoride was supposed to be added, the Sunday Mirror carried many letters from people who could taste the difference and felt a variety of symptoms. On Monday the Medical Office of Health announced that a technical hitch meant that the fluoride would not in fact be added for another month. There were no further protests.
Thirty years later I was regional director of public health for the West Midlands (which includes Birmingham). From time to time the issue of fluoridation was raised, most often as some sort of scare about cancer, bone fractures, dental fluorosis, or allergies. A little over half of the region was fluoridated, and we knew in some detail which areas had fluoridated water and which did not. We examined every claim made against fluoride, and like most of the international public health agencies we were never able to find any evidence of the various allegations of harm. We even found that the incidence of some cancers seemed to be less in fluoridated areas, although such results may be due to chance.
We looked at most cancers and a range of other conditions, particularly in bones. We found it impossible to get any of this work into major journals; we were told that such studies were old hat. I remember being attacked for wasting time at the conference of the International Association of Cancer Registries. “Everyone knows about fluoride,” I was told. “We know that it does no harm. The reasons why people protest about it have nothing to do with health.”
Media interest has fluctuated over the years. I was once invited to defend our fluoridation policy on BBC Radio 4's You and Yours consumer affairs programme in a debate with John Yiamouyiannis, a famous US campaigner against fluoridation. I described our studies, and Dr Yiamouyiannis replied that there was no point in doing such studies in England because the English drank a lot of tea, which has so much fluoride in it that it would mask any differences that might occur from putting fluoride in the drinking water. I said I was sure that listeners would be pleased to know that fluoride in the water was no more dangerous than drinking tea. You and Yours cut that section; I don't know why.
Too much fluoride can lead to fluorosis: mottling of the teeth. Is this a problem? Dentists say that they can detect it in a proportion of patients in fluoridated areas, but I've never heard anyone complain about it outside fluoridation debates. Birmingham has had fluoride for 40 years; if fluorosis was a major problem I ought to have heard jokes about Brummies and their funny teeth by now.
Another issue that has caused some confusion over the years is natural fluoride in water. For geological reasons rivers and ground water in some areas have more fluoride; in fact it was the good dental health of people in those areas that first led to the idea of artificial fluoridation of water supplies. It is irrational to behave as though natural fluoride is somehow fine while artificial fluoridation is not. In our urbanised world there is really no such thing as natural water supplies in much of the country. Birmingham, Manchester, and Liverpool get their water from Wales—is that “natural”?
The important question is whether fluoridation does any good. On balance, it seems that it does. Dental health in the fluoridated areas of the West Midlands is among the best in the country, even though we are far from best on other indicators, such as obesity, heart disease, and life expectancy. Is it really possible that the West Midlands has a diet that gives it the best teeth in the country and also a high prevalence of obesity among women?
Clearly, it would be better if there was evidence that met modern standards, but how many trials conducted between 1930 and 1960 would meet those standards? It may be true that there could be hazards from fluoride at levels that we cannot detect, and for academic researchers this may well matter. But the key question I was asked as regional director of public health was whether we should take the fluoride out of Birmingham's water. My answer has always been no, because I could not detect any harm with the tools that were available to me. I always made it clear that if evidence of harm were to emerge then we would stop the fluoridation. If we stopped fluoridation the population of Birmingham would end up with worse dental health, as has happened in the places where fluoridation schemes have been stopped. Furthermore the burden would tend to fall unequally: poorer children would get more dental problems than rich children.
Of course, the issue must be debated. Any large scale public health measure involves judgment about the balance of probabilities, and it would be exceptional for a population based measure to have no possible risk of harm to anyone. The ethical debate over fluoridation happens precisely because it is a population measure; if it were a drug then individuals could make decisions about their own compliance.
What remains surprising and under-researched is the vehemence of some people's opinions on the matter. The general public do not know much about fluoridation; for instance, surveys have shown that many people believe that their water is fluoridated when it is not. Why do some people become so passionate about fluoride, when other regulations about harmful chemicals to which we are all exposed through agriculture and industry attract so much less attention?
Why do some people become so passionate about fluoride, when other regulations about harmful chemicals to which we are all exposed attract so much less attention?