The Systematic Review of Water Fluoridation commissioned last summer by the Department of Health has reported at last (BMJ, 6 October 2000 and NHS CRD Report No 18). It had been hugely misrepresented by leaks in advance from the British Dental Association and the public health press, and was never trusted from the start by opposition groups such as the National Pure Water Association. Both camps predicted that the review “would endorse fluoridation as safe and effective”. And both are wrong. Embarrassingly, cringingly, wrong.
As a member of the review committee, I can now present the facts of the matter.
The key finding was the poor quality and quantity of acceptable evidence. Only 24 studies of dental benefit and 88 studies of fluorosis qualified for review. They differ widely and must be interpreted with extreme caution.
In general, these studies indicate that fluoridation inflicts on teeth at least as much harm as good. For every mouth cleared of dental decay by fluoridation, another gets fluorosis of “aesthetic concern” bad enough to justify cosmetic correction. The benefit is far less, and the fluorosis much more, than have been claimed. Observer bias may be inflating the benefit and underestimating the damage a possibility that is being explored in more detail.
Other findings are that fluoridated toothpaste does not appear to alter the impact of fluoridated water, and fluoridation has very little if any effect on the social class divide in dental decay.
Clearly, this is not an acceptable trade off. Indeed, it may account for the observed increase in dental costs per head in fluoridated areas a topic the review did not cover.
There, of course, lies the principal bone of contention. The terms of reference confined the review to the effects of water fluoridation an old ploy to fudge the issue perhaps, but also a legitimate part of the Cochrane protocol under which the review was conducted. This shut out the effect of fluorides from other sources food and drink, dental toiletries and airborne pollution whose extent is largely unknown.
NHS doctors do not have routine access to tests for fluoride in their patients’ blood or urine, so we have few data on how or why fluoride exposure varies between individuals. The fluoride laboratory I direct has demonstrated a wide profile of total fluoride exposure across the population (Fluoride, 1999; 32: 27-32), and several highly exposed individuals whose symptoms improved when their fluoride consumption was reduced. It suggests that most of the surprisingly large amounts of fluoride consumed by British residents must come from sources other than water (Lancet 2000; 355: 1644-5).
Water fluoridation cannot, therefore, be judged in isolation. Any adverse effects must be related to total fluoride consumption, and need to be actively looked for by doctors, supported by appropriate tests, in a way never previously done before in this country.
Other possible adverse effects of fluoride in water hip fracture, cancer, Down’s syndrome, mental dysfunction, infant mortality and thyroid disease can also be caused by factors other than fluoride. To specifically distinguish the influence of fluoride requires that fluorides from all sources be taken into account which the review ruled out. It was therefore no surprise to find no
consistent effect due to water fluoride alone a minor part of total exposure.
The review stresses that its findings must be taken in the context of other relevant evidence, plus ethical, environmental, ecological, economic and legal factors. Nevertheless, the former Minister who commissioned the review explicitly intended that legislation enabling wider fluoridation should stand or fall by its findings.
This review has changed the minds of many of the scientists involved and, although some may try to claim vindication, they cannot escape one sobering fact: every benefit is balanced with an equal or larger dose of harm against a general background of ignorance and bad science. This conclusion cannot remotely be justified. There is no overall public health benefit or cost savings in using fluoride in the way that has evolved.
In the research field, monitoring the long term adverse effects of overall exposure to fluorides is lamentably deficient, particularly given the current high rates of fluoride exposure due to its presence in so many items, in particular, dental products. There is an urgent need to define the effects of a lifetime of exposure to the industrial fluorides used in water: there is no evidence to justify equating them with natural fluoridation. A few well designed, comprehensive studies are needed to resolve these doubts. Such studies must include the measurement of total fluoride intake in each and every study participant.
In the NHS, doctors and dentists should be alerted to the symptoms that may present in their patients, and there should be routine NHS fluoride tests for patients with relevant symptoms, with training on how to interpret the results.
Meanwhile, legislation to extend fluoridation schemes more widely would be profoundly irresponsible. We have not monitored the range of total fluoride consumption. Some individuals are certainly consuming excessive fluoride for years, unknowingly and undetected, and adding it to water just makes that worse.
The review has exposed black holes not in teeth, but in fluoridation science and clinical practice. Public health authorities must make amends.
!ADr Peter Mansfield
For full information, visit www.good healthkeeping.com/brief/Fluoride.htm or send an A5 SAE plus four separate first class stamps to F-lab, PO Box 6, Louth LN11 8XL