FAN Bulletin 882
October 5, 2007
Dear All,
Forgive this long bulletin – but it will be the last for some time. I am off to China tomorrow to attend the International Society for Fluoride Research (ISFR) conference in Beijing and then on to Australia to help communities fight off fluoridation in Victoria, NSW and Queensland. I will be back on November 1. Meanwhile, I hope everyone will try to get the number up on the Online petition to Congress. See the home page http://www.FluorideAction.net for the way to sign on. While I am away don’t forget to track the latest news – home page – left hand side.
In albeit genteel language three leading UK scientists delivered a blistering condemnation of UK policy on promoting fluoridation in today’s issue of the British Medical Journal (BMJ). They point out that the UK government has funded the unabashed propagandist activities of the British Fluoridation Society and the government also twisted the findings of the York Review to suit their agenda of promoting fluoridation.
The BMJ, perhaps in order to soften the blow to the British dental establishment, also printed a fluffy anecdotal piece from Rod Griffiths, retired doctor and former regional director of public health, West Midlands. John Graham of the National Pure Water Association in the UK points out that Griffiths in his opening remarks uses a PR tactic which has been used countless times before in the history of fluoridation promotion. The tactic was documented by Dr. George Waldbott in his book “A Struggle with Titans” published by Carlton Press, New York, 1965. John quotes Waldbott as follows:
Chapter Ten, page 195
“A widely used promotional story has been circulated about Akron, O.; San Francisco, Calif.; Newburgh and Elmira, N. Y.; Charlotte, N. C.; E. Lansing, Mich.; Brantford, Ont., and many other places. It goes like this: Citizens swamped city hall with complaints of illness due to drinking fluoridated water when, to everyone’s dismay, it was discovered that somehow fluoridation had not, as yet, been put into operation.
Since the same events are alleged to have occurred in many cities and since, according to the story, after introduction of fluoridation in the above-named cities no further complaints were registered, the veracity of the story is doubtful.”
The article by Cheng et al. could have been a lot stronger had not the commentators taken such an anglocentric view of the issue. For example, they fail to mention the National Research Council review of 2006, which has to be the most comprehensive overview of the toxicology of fluoride ever written. Moreover, the NRC review authors, unlike the York Review (McDonagh, et al, 2000), on which the authors of the BMJ piece seem to solely rely, did not limit themselves to epidemiological studies but availed themselves of all the evidence which might point to fluoride’s ability to do harm: epidemiological studies, clinical trials, animal studies, toxicological studies and theoretical models.
I would argue that if you are considering dosing the whole population with a substance known to be highly toxic, known to have ravaged millions of people in India and China where natural levels are high, then one should avail oneself of ALL the data that might indicate potential harm. The NRC review did this. The York review did not – preferring the more limited tool of meta-analysis.
Let me give just two examples of the limitations of the York Review (for which I was an invited peer reviewer).
When considering benefits the authors chose to limit themselves to longitudinal studies when some of the more convincing evidence of fluoridation’s ineffectiveness has come from cross-sectional studies. Longitudinal studies consider the same community at two different points in time. Cross-sectional studies compare communities at the same time. The largest and most expensive study ever conducted in the US was a cross-sectional study where the tooth decay of 39,000 children was compared in 84 communities. In this study Brunelle and Carlos (1990) found that children who had lived all their lives in a fluoridated community had an average saving of six tenths of one tooth surface (out of over 100 tooth surfaces in a child’s mouth) compared to children living all their lives in a non-fluoridated community. How much risk would one take to save 0.6 of a tooth surface? Other cross-sectionals studies have found even less difference (Spencer et al. 1996) and others none (Armfield & Spencer, 2004). Figures published by the NY State Department of Health based on a survey of tooth decay in third graders (2002-04) – average by county – showed absolutely no relationship to the percentage of the county population drinking fluoridated water. Dr. Bill Osmunson has found a similar non-relationship when the percentage of children with good or excellent teeth (average by state) were plotted against the 50 states in order of the percentage of the population drinking fluoridated water. He did this for children from both high and low income families and both plots are essentially flat – no relationship with the degree of fluoridation. People can nitpick about confounding variables but Bill controlled for the biggest one – income levels. The trend is obvious and it does not need a rocket scientist or meta-analysis to see it.
It is interesting that the BMJ authors who having eschewed cross-sectional studies in the York Review, actually turn to a cross-sectional comparison in their first figure where they compared declines in tooth decay in several European countries using WHO figures. In doing this they essentially “borrowed” (without acknowledgement) the approach developed by Chris Neurath and used on our web site for several years, and subsequently published in the journal Fluoride. But we are not upset as it is in a good cause!
The second limitation of the York review was restricting themselves to effects at 1 ppm. So when they looked at the important Li et al. (2001) study (pre-publication copy) they considered that this study showed no difference in hip fractures in the elderly in two villages less than 1 ppm and the village (control) at 1 ppm. However, this same study showed a doubling of hip fractures at 1.5 ppm (not statistically significant) and a tripling above 4 ppm (statistically significant). The latter finding and the possible trend would be really important to someone trying to determine an adequate margin of safety to protect say high water consumers or people with kidney impairment from lifelong exposure to fluoride, but was not revealed by the meta-analysis used in the York Review.
One final comment: the British commentators correctly criticize the MRC for funding the pathetic study of 20 people to compare body accumulations of fluoride in people living in natural and artificially fluoridated areas, but they fail to mention that this “august” body committed worse sins. The MRC gave more priority to further studies on dental fluorosis than studies on the central nervous system, the endocrine system, the reproductive system or the kidney!
I do hope now that these three authors will read the NRC (2006) review and write another piece for the BMJ.
Meanwhile, we have to be grateful that this has raised an alarm about the British government’s bias in this matter and at least one major British newspaper, The Guardian (see below) and MedicalNewstoday.com, see http://www.medicalnewstoday.com/articles/84666.php
Paul Connett
—————————
THE GUARDIAN
Senior doctors allege lack of evidence on fluoride safety
Sarah Boseley, health editor
Friday October 5, 2007
The Guardian
reader@guardian.co.uk
The government is accused by senior doctors today of selectively using inadequate evidence to promote the use of fluoride in the water supply. The public health measure, intended to improve the country’s teeth, has attracted huge controversy. Anti-fluoride campaigners claim the chemical has potentially harmful side-effects, while dentists and some public health experts insist it is entirely beneficial and saves children from tooth decay.
In the British Medical Journal today, Sir Iain Chalmers, editor of the James Lind Library, which was set up to help people understand the evidence base of medicine, KK Cheng, professor of epidemiology at Birmingham University, and Trevor Sheldon, professor and pro-vice-chancellor at York University, say there is not enough evidence either way. They accuse the government of “one-sided handling of the evidence” and add that “the Department of Health’s objectivity is questionable”, pointing out that until last year it funded the British Fluoridation Society, set up in 1969 to push for fluoride to be added to water supplies in more areas. It is up to local health authorities to decide whether fluoridisation (sic) should happen in their region.
In 1999, the Department of Health commissioned a systematic review of the evidence by York University. “Given the certainty with which water fluoridation has been promoted and opposed … the reviewers were surprised by the poor quality of the evidence and the uncertainty surrounding the beneficial and adverse effects,” they write.
Even the studies to show the benefits on teeth were few and inconsistent, they say. The rate of dental caries caused by tooth decay has dropped substantially both in countries which have added fluoride, such as Germany and Portugal, and those which have not, such as Austria and Sweden. There is strong evidence that using toothpaste containing fluoride reduces tooth
decay.
Studies on the side-effects of fluoride in water were low-quality and it is hard to estimate how many people would suffer mottled teeth, and not possible to reach conclusions on other alleged harm, such as bladder cancer and bone fracture, they say. “There is no such thing as absolute certainty on safety,” they write.
But the Department of Health used the York findings “selectively”, they write, “to give an over-optimistic assessment of the evidence in favour of fluoridation.” It commissioned research on the effects of water in which fluoride naturally occurred, but on only 20 people. This, together with the York review, formed the basis of the government’s safety claims, they say.
They call for proper randomised controlled trials.
In a comment piece in the journal, Rod Griffiths, regional director of public health for the West Midlands, credits 40 years of fluoridation for the excellent teeth of the people of Birmingham, in spite of their poor record on obesity and heart disease.
The DoH said it “makes no apologies for promoting the benefits to oral health which fluoridation offers”. The York review showed fluoridation increased the number of children without tooth decay by 15%, it said in a statement, and adults in those areas had 27% less caries.
The department was committed to further research to strengthen the evidence base, it said in a statement.
http://politics.guardian.co.uk/publicservices/story/0,,2184087,00.html
What do you think?
Email your comments for publication to politics.editor@guardianunlimited.co.uk
—————
BRITISH MEDICAL JOURNAL
BMJ 2007;335:699-702 (6 October)
http://www.bmj.com
Analysis
Controversy
Adding fluoride to water supplies
K K Cheng, professor of epidemiology1, Iain Chalmers, editor2, Trevor A Sheldon, professor and pro-vice chancellor3
1 Public Health Building, University of Birmingham, Edgbaston, Birmingham B15 2TT , 2 James Lind Library, Oxford OX2 7LG , 3 Health Services Research, University of York, York YO10 5DD
Correspondence to: K K Cheng k.k.cheng@bham.ac.uk
Adding fluoride to water supplies to prevent dental caries is controversial. K K Cheng, Iain Chalmers, and Trevor A Sheldon identify the issues it raises in the hope of furthering constructive public consultation and debate
Several countries add fluoride to water supplies to prevent dental caries (boxes 1 and 2). Since the 2003 Water Act, water companies are required to add fluoride to supplies when requested—after public consultation—by a health authority in England or the Welsh Assembly in Wales.(1)
Summary points
Water fluoridation is highly controversial. Evidence is often misused or misinterpreted and uncertainties glossed over in polarised debates. Problems include identifying benefits and harms, whether fluoride is a medicine, and the ethical implications. This article provides professionals and the public with a framework for constructive public consultations
Box 1 Dental caries
What is dental caries?
Dental caries is a process of demineralisation of dental hard tissue caused by acids formed from bacterial fermentation of sugars in the diet. Demineralisation is countered by the deposit of minerals in the saliva—remineralisation. Remineralisation is a slow process, however, which has to compete with factors that cause demineralisation. If remineralisation can effectively compete the enamel is repaired. If demineralisation exceeds remineralisation a carious cavity finally forms. Fluoride prevents caries by enhancing remineralisation.
How common is caries?
The figure
FIGURE
Tooth decay in 12 year olds in European Union countries (2)
Box 2 Exposure to fluoride
How common are water supplies containing fluoride?
About 9-10% of water supplies in England and Wales contain 0.5-1 mg/l fluoride, either naturally or as an additive. (2) (3) (4). Limited fluoridation trials were introduced in England from the mid-1950s, but resistance by water companies curtailed their spread. Currently, 1.5 million people receive water containing fluoride drawn from ground that is relatively high in the mineral. Another five million people in parts of the West Midlands, Yorkshire, and Tyneside receive water with added fluoride (1 mg/l). Fluoride is not added to water supplies in Scotland, Wales, or Northern Ireland. In Western Europe 12 million people receive water with added fluoride, mainly in England, Ireland, and Spain.(5) In the United States, just under 60% of the population receive fluoridated water. (6) Water fluoridation has also been introduced in Australia, Brazil, Chile, Colombia, Canada, Hong Kong Special Administrative Region of China, Israel, Malaysia, and New Zealand. Worldwide, about 5.7% of people receive water containing fluoride to around 1 mg/l. (5) In some countries such schemes have been withdrawn. These include Germany, Finland, Japan, the Netherlands, Sweden, and Switzerland. Systematic information on the rationale behind these decisions is not available. In the Swiss canton of Basel-Stadt, the fluoridation scheme was withdrawn in 2003 after 41 years of operation because other measures were of “comparable effectiveness” to “compulsory medication.” (7)
What are the sources of fluoride exposure?
Before the widespread use of fluoride containing toothpastes, fluoride in water (natural or fluoridated) was the main source of exposure in adults and children.(8) Although the relative contribution from toothpaste has increased, in fluoridated areas drinking water remains the main source of exposure. Young children are more likely to ingest fluoridated toothpaste, so its relative importance as a source of exposure is higher in children than in adults.
Plans to add fluoride to water supplies are often contentious. Controversy relates to potential benefits of fluoridation, difficulty of identifying harms, whether fluoride is a medicine, and the ethics of a mass intervention. We are concerned that the polarised debates and the way that evidence is harnessed and uncertainties glossed over make it hard for the public and professionals to participate in consultations on an informed basis. Here, we highlight problems that should be confronted in such consultations and emphasise the considerable uncertainties in the evidence.
Known benefits of adding fluoride to water
In 1999, the Department of Health in England commissioned the centre for reviews and dissemination at the University of York to systematically review the evidence on the effects of water fluoridation on dental health and to look for evidence of harm. (9) The review was developed with input from an advisory committee, which included members who supported and opposed fluoridation, or who had no strong views on the matter. Exceptional steps were taken to avoid bias and ensure transparency throughout.
Given the certainty with which water fluoridation has been promoted and opposed, and the large number (around 3200) of research papers identified, (9) the reviewers were surprised by the poor quality of the evidence and the uncertainty surrounding the beneficial and adverse effects of fluoridation.
Studies that met the minimal quality threshold indicated that water fluoridation reduced the prevalence of caries but that the size of the effect was uncertain. Estimates of the increase in the proportion of children without caries in fluoridated areas versus non-fluoridated areas varied (median 15%, interquartile range 5% to 22%). These estimates could be biased, however, because potential confounders were poorly adjusted for. (9)
Water fluoridation aims to reduce social inequalities in dental health, (10) but few relevant studies exist. The quality of research was even lower than that assessing overall effects of fluoridation. The results were inconsistent—fluoridation seemed to reduce social inequalities in children aged 5 and 12 when measured by the number of decayed, missing, or filled teeth, but not when the proportion of 5 year olds with no caries was used.
Potential harms of fluoridation
The review estimated the prevalence of fluorosis (mottled teeth) and fluorosis of aesthetic concern at around 48% and 12.5% when the fluoride concentration was 1.0 part per million, (9) although the quality of the studies was low. The evidence was of insufficient quality to allow confident statements about other potential harms (such as cancer and bone fracture). The amount and quality of the available data on side effects were insufficient to rule out all but the biggest effects.
Small relative increases in risk are difficult to estimate reliably by epidemiological studies, even though lifetime exposure of the whole population may have large population effects. For example, an ecological study from Taiwan found a high incidence of bladder cancer in women in areas where natural fluoride content in water is high. The authors attributed the finding to chance because multiple comparisons were made.(11) Testing the hypothesis that drinking fluoridated water increases the risk of bladder cancer would need to take account of errors in estimating total fluoride exposures; potential lack of variation in exposure; the probable long latency between exposure and outcome; the presence of strong confounders such as smoking and occupational exposures; and changes in diagnostic classification of bladder tumours. Therefore, a modest association between fluoridation and bladder cancer would be difficult to detect, both in communities and in individuals. This is of concern because a modest (for example, 20%) increase in risk of bladder cancer would mean about 2000 extra new cases a year if the entire UK population was exposed.
The methodological challenges of detecting harms of long term exposure to fluoridation are further illustrated by a case-control study on hip fracture in England. (12) It reported “no increase” in risk associated with average lifetime exposure of 0.9 part per million fluoride in drinking water. Although exemplary in many other aspects, the study had less than 70% power to identify an odds ratio of 1.5 associated with exposure. If the odds ratio was only 1.2—which would mean more than 10 000 excess hip fractures a year in England if the population was so exposed—the study would have a less than one in five chance of detecting it.
Thus, evidence on the potential benefits and harms of adding fluoride to water is relatively poor. This is reflected in the recommendations of the Medical Research Council (MRC) (13) and the Scottish Intercollegiate Guideline (14) on preventing and managing dental decay in preschool children (box 3). We know of no subsequent evidence that reduces the uncertainty.
Box 3 Key recommendations for future research on water fluoridation
“Studies are needed to provide estimates of the effects of water fluoridation on children aged 3-15 years against a background of widespread use of fluoride toothpaste, and to extend knowledge about the effect of water fluoridation by . . . (socio-economic status), taking into account potentially important effect modifiers such as sugar consumption and toothpaste usage” (13)
“A robust evaluation of the benefits of water fluoridation, as well as the potential risks of fluorosis . . . should be a health priority” (14)
There is no such thing as absolute certainty on safety. While the quality of evidence on potential long term harms of fluoridated water may be no worse than that for some common clinical interventions, patients can weigh potential benefits and risks before agreeing to treatments. In the case of fluoridation, people should be aware of the limitations of evidence about its potential harms and that it would be almost impossible to detect small but important risks (especially for chronic conditions) after introducing fluoridation.
Alternative ways to prevent caries
The evidence from systematic reviews of randomised trials is strong for alternative ways of preventing caries—mainly toothpastes containing fluorides. Analysis of 70 randomised trials of 42,300 children yielded a pooled preventive fraction for decayed, missing, or filled teeth of 24% (21% to 28%). (15) However, the use of toothpastes depends on individual behaviour, which has implications for reducing inequality.
Is fluoride added to water supplies a medicine?
Fluoride is not in any natural human metabolic pathway. Because it mainly reduces caries by remineralisation of demineralised enamel (box 4), some people regard water fluoridation as a form of mass medication. Other people point out that fluoride occurs naturally at concentrations comparable to those used in fluoridation programmes and is therefore not a medicine. If viewed as a medicine, water fluoridation would require approval from a relevant authority.
Box 4 Effect of fluoride on the association between sugar and caries
Fluoride is the main factor that alters the resistance of teeth to acid attack and interacts with sugars in plaque. Fluoride affects tooth structure during and after development. It reduces caries in three ways:
It reduces and inhibits dissolution of enamel
It promotes remineralisation; remineralisation in the presence of fluoride not only replaces lost mineral but also increases resistance to acids and to subsequent demineralisation
It affects plaque by altering the ecology of the dental plaque and reducing acid production
Fluoride is most effective when used topically, after the teeth have erupted
The legal definition of a medicinal product in the European Union (Codified Pharmaceutical Directive 2004/27/EC, Article 1.2) is any substance or combination of substances “presented as having properties for treating or preventing disease in human beings” or “which may be used in or administered to human beings either with a view to restoring, correcting or modifying physiological functions by exerting a pharmacological, immunological or metabolic action.” Furthermore, in 1983 a judge ruled that fluoridated water fell within the Medicines Act 1968, “Section 130 defines ‘medicinal product’ and I am satisfied that fluoride in whatever form it is ultimately purchased by the respondents falls within that definition.” (16)
If fluoride is a medicine, evidence on its effects should be subject to the standards of proof expected of drugs, including evidence from randomised trials. If used as a mass preventive measure in well people, the evidence of net benefit should be greater than that needed for drugs to treat illness. (17) An important distinction also exists between removing unnatural exposures (such as environmental tobacco smoke) and adding unnatural exposures (such as drugs or preservatives). (18) In the second situation, evidence on benefit and safety must be more stringent. There have been no randomised trials of water fluoridation.
Ethical implications
Under the principle of informed consent, anyone can refuse treatment with a drug or other intervention. The Council of Europe Convention on Human Rights and Biomedicine 1997 (19) (which the UK has not signed) states that health interventions can only be carried out after free and informed consent. The General Medical Council’s guidance on consent also stresses patients’ autonomy, and their right to decide whether or not to undergo medical intervention even if refusal may result in harm. (20) This is especially important for water fluoridation, as an uncontrollable dose of fluoride would be given for up to a lifetime, regardless of the risk of caries, and many people would not benefit.
The convention makes provision for exceptions to the principle of informed consent if necessary for public safety, to prevent crime, or to protect public health (article 26). (19) Potential benefit must therefore be balanced against uncertainty about harms, the lower overall prevalence of caries now than a few decades ago (and smaller possible absolute benefit), the availability of other effective methods of prevention, and people’s autonomy. Research on areas suggested by the MRC is needed. (13) Methodological challenges due to problems of measuring fluoride exposure, long latency in chronic disease, and modest effect sizes will need special attention.
Trust in the dissemination of evidence
Public and professional bodies need to balance benefits and risks, individual rights, and social values in an even handed manner. Those opposing fluoridation often claim that it does not reduce caries and they also overstate the evidence on harm. (21). On the other hand, the Department of Health’s objectivity is questionable—it funded the British Fluoridation Society and, along with many other supporters of fluoridation, it used the York review’s findings (9 ) selectively to give an overoptimistic assessment of the evidence in favour of fluoridation. (22) In response to MRC recommendations, (13) the department commissioned research on the bioavailability of fluoride from naturally and artificially fluoridated drinking water. The study had only 20 participants and was too small to give reliable results. Despite this and the caveats in the report’s conclusion, (23) this report formed the basis of a series of claims by government for the safety of fluoridation. (24)
Against this backdrop of one sided handling of the evidence, the public distrust in the information it receives is understandable. We hope this article helps provide professionals and the public with a framework for engaging constructively in public consultations.
We thank Edward Baldwin, June Jones, Aubrey Sheiham, and David Sloan for their comments on the manuscript.
Contributors and sources: All authors contributed to the original idea of the paper and its writing. TAS chaired the CRD fluoridation review advisory panel. IC was a member of the same panel. KKC lives in Birmingham where the water is fluoridated. The sections on potential benefits and harms of water fluoridation are largely based on a systematic review and recent materials identified through Medline searches. The rest of the paper reflects the authors’ opinion. KKC is guarantor.
Competing interests: Please see the Contributors and sources section.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
1. Drinking Water Inspectorate. Fluoridation of drinking water. 2006. www.dwi.gov.uk/consumer/concerns/fluoride.shtm
2. WHO. WHO oral health country/area profile programme.www.whocollab.od.mah.se/expl/regions.html
3. Whelton HP, Ketley CE, McSweeney F, O’Mullane DM. A review of fluorosis in the European Union: prevalence, risk factors and aesthetic issues. Community Dent Oral Epidemiol 2004;32(suppl 1):9-18.[CrossRef]
4. Jowell T. House of Commons official report (Hansard). 1998 May 6: col 697. http://tinyurl.com/3xvxwc.
5. National Public Health Service for Wales. Briefing paper on fluoridation and the implications of the Water Act 2003. 2004. http://tinyurl.com/2onuvw.
6. Centre for Disease Control. Fluoridation statistics 2002: status of water fluoridation in the United States. 2002. www.cdc.gov/fluoridation/fact_sheets/us_stats2002.htm
7. Gesundheits-und Sozialkommission des Kantons Basel-Stadt. Bericht der Gesundheits-und Sozialkommission des Grossen Rates zum Anzug René Brigger betreffend Fluoridierung des Basler Trinkwassers. P975485. 2003. www.bruha.com/pfpc/ber-9229_Basel_document.pdf
8. Murray JJ, Rugg-Gunn AJ, Jenkins GN. Fluorides in caries prevention. 3rd ed. Oxford: Wright, 1991.
9. NHS Centre for Reviews and Dissemination. A systematic review of public water fluoridation. York: NHS CRD, 2000.
10. Locker D. Deprivation and oral health: a review. Community Dent Oral Epidemiol 2000;28:161-9.[CrossRef]
11. Yang CY, Cheng MF, Tsai SS, Hung CF. Fluoride in drinking water and cancer mortality in Taiwan. Environ Res 2000;82:189-93.[Medline]
12. Hillier S, Cooper C, Kellingray S, Russell G, Hughes H, Coggon D. Fluoride in drinking water and risk of hip fracture in the UK: a case-control study. Lancet 2000;355:265-9.[CrossRef]
13. Medical Research Council. Working group report: water fluoridation and health. London: MRC, 2002.
14. Scottish Intercollegiate Guidelines Network. Prevention and management of dental decay in the pre-school child: a national clinical guideline. SIGN, 2005. www.guideline.gov/summary/summary.aspx?doc_id=8395http://www.sign.ac.uk/pdf/sign83.pdf.
15. Marinho VC, Higgins JP, Sheiham A, Logan S. Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev 2003;(1):CD002278.
16. Lord Jauncey. Opinion of Lord Jauncey in causa Mrs Catherine McColl (A.P) against Strathclyde Regional Council. The Court of Session, Edinburgh, 1983.
17. Cochrane AL, Holland WW. Validation of screening procedures. Br Med Bull 1971;27:3-8.[Free Full Text]
18. Rose G. The strategy of preventive medicine. New York: Oxford University Press, 1993.
19. Council of Europe. Convention for the protection of human rights and dignity of the human being with regard to the application of biology and medicine: convention on human rights and biomedicine. Council of Europe, 1997. http://conventions.coe.int/treaty/en/treaties/html/164.htm
20. General Medical Council. Seeking patients’ consent: the ethical considerations. London: GMC, 1998.
21. Connett P. Fifty reasons to oppose fluoridation. Fluoride Action Network, 2004. www.fluoridealert.org/50-reasons.htm
22. Wilson PM, Sheldon TA. Muddy waters: evidence-based policy making, uncertainty and the “York review” on water fluoridation. Evidence Policy 2006;2:321-31.
23. Maguire A, Moynihan PJ, Zohouri V. Bioavailability of fluoride in drinking-water—a human experimental study. Report for the UK Department of Health, June 2004. Newcastle upon Tyne: School of Dental Sciences, University of Newcastle, 2004.
24. Lord Warner. House of Lords Official Report (Hansard). 2004 June 29: col WA6. http://tinyurl.com/37hgel
(Accepted 15 July 2007)
—————————————————–
Related Article
BMJ 2007;335 (6 October)
Editor’s Choice
Tooth and nail
Fiona Godlee, editor
fgodlee@bmj.com
If you’re interested in what BMJ editors do when they are out and about, there’s a new blog on bmj.com (http://blogs.bmj.com/bmj/category/comment/editors-at-large). It gives a flavour of some of the conferences we’ve been at and some of the people we’ve met: the eponymous Dr Kawasaki for one, UK public health grandee Rod Griffiths for another. I met Rod at a conference in Athens and we got talking about fluoride. No one in their right mind would get involved in the debate about water fluoridation, he said. It’s a minefield. But this week we do get involved, and against his better judgment, so does Rod.
In the Analysis section KK Cheng, Iain Chalmers, and Trevor Sheldon summarise the problems that bedevil reasoned discussion on whether fluoride should be added to water supplies. Highly polarised disputes are fuelled by misuse of what little evidence there is, and the Department of Health is not innocent of this, they say. It commissioned a systematic review, to which two of the authors contributed but then, in Cheng and colleagues’ view, misrepresented the findings in fluoride’s favour.
Objective though they strive to be, my reading is that Cheng and colleagues come down against fluoridation because of uncertainty about its safety, questions of autonomy, and because there are other ways of preventing caries. Meanwhile, at my invitation Rod Griffiths tells us how, as regional director for public health, he took on an already fluoridated water supply and consistently defended it because he saw no evidence of harm and some of benefit. Cheng and colleagues want more and better research on fluoride’s effects. Griffiths wants research into why people get so worked up about it all.
Evidence on fluoride may be lacking, but there’s a growing body of evidence and experience on the effects (largely adverse) of direct to consumer advertising…
——————————————
BMJ 2007;335:723 (6 October)
Views & reviews
Personal views
Fluoride: a whiter than white reputation?
Rod Griffiths, retired doctor and former regional director of public health, West Midlands
rod@stonebow.demon.co.uk
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?
Posted by Editor
in FAN
0 comments
