fluoridation – does it work

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Fluoridation – does it work?RCPSG Triennial Conference

6th November 2008

I.G. ChestnuttProfessor and Hon Consultant in Dental Public Health

Cardiff University School of Dentistry


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Fluoridation - does it work?

• Fluoridation – the addition/adjustment of fluoride to/in the public water supply with the intention of preventing dental caries

• Does it work?

• As a caries preventive agent• As a public health policy

• Is it safe?


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Current fluoridation status in the U.K.

• About 6 million people in the U.K currently drink fluoridated water– 3.5M in the West

Midlands– 1.7M in the North East

• No artificial fluoridation schemes in Scotland, Wales or N Ireland


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Fluoridation – the early years

Colorado Stain

•Distinct geographic distribution

•Lifetime-residents

•Linked to water supply

•Fluoride was the causative agent

•Affected individuals no more likely to have caries

Dean’s contribution

•Dose response – fluoride and caries

•1ppm optimal dose

Grand Rapids / Muskegon / Aurora study

50% reduction in Grand Rapids vs Muskegon after 6.5yrs


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“Water fluoridation significantly improves health and reduces inequalities”

“The present legislation on fluoridation is not working”

“We have commissioned an expert scientific review of fluoride and health”

Fluoridation - the recent years

Saving lives – our healthier nation


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The York Report

• What are the effects of fluoridation of drinking water supplies on the incidence of dental caries?

• If water fluoridation is shown to have beneficial effects, what is the effect over and above that offered by the use of alternative interventions and strategies?

• Does water fluoridation result in a reduction of caries across social groups and between geographical locations bringing equity?

• Does water fluoridation have negative effects?

• Are there differences in the effects of natural and artificial water fluoridation?


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The increase in proportion of caries free children in

fluoridated compared with non-fluoridated communities

• Does fluoridation prevent dental cares?

• The best available evidence suggests that the difference in the change in caries prevalence from baseline to final examination in fluoridated compared to non-fluoridated areas was 14.6% caries free or 2.25 DMFT

• This probably equates to a preventive fraction of about 40% (Worthington and Clarkson 2003)

• BUT


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The limitations of the evidence

• The studies (of caries preventive effects of fluoridation) were of moderate quality and of limited quantity

• Many excluded because there were cross-sectional in design

• Only 26 studies included – mainly before- after studies, 2 prospective cohorts, 1 retrospective cohort– Frequently lack of appropriate analysis to control for

potentially confounding factors


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Adverse effects of fluoridation –

Bone fracture incidenceIs fluoridation safe?

• No association could be found between fluoridation and– Bone fracture– Bone cancer

• Overall studies examining other possible negative effects provide insufficient evidence on any particular outcome to permit confident conclusions


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Fluoridation and FluorosisFluoride Level % population with fluorosis of aesthetic

concern

0.1 6.3

0.2 6.9

0.4 8.2

0.7 10.0

1 12.5

1.2 14.5

2 24.7

4 63.4

• Most widely studied side effect of fluoridation

• At 1ppm it was estimated that the prevalence of fluorosis of “aesthetic concern” would be 12.5%

• Although 88 studies were included, they were of low quality


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How York has been interpreted - by the pros

• “many studies have confirmed that water fluoridation reduces tooth decay, and has no serious side effects”

• The main discussion on the York review describes its conclusions without sufficiently drawing out of the degree of cautioness that was central to the reports findings.

(Working Party, Nuffield Council on Bioethics, 2007)

(BFS, 2004)


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How York has been interpreted - by the antis• “The York Review Fiasco”

• “Sham review that deliberately excluded studies that would show fluoridation in a bad light”

• Fluoride causes brain damage and lowered IQ in children

• Fluoridation causes unsightly discolouration of teeth

• The York Review noted in relation to adverse events …there was not enough good quality evidence to reach conclusions.


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Cheng, Chalmers & Sheldon, BMJ, Oct 2007

Lennon, Beal & Rugg-Gunn, CDH, March 2008

…. Those opposing fluoridation often claim that it does not reduce caries and they also overstate the evidence on harm. 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 selectively to give an overoptimistic assessment of the evidence in favour of fluoridation. ….


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Does it work as a caries preventive agent?

• So, it works but the evidence isn’t up to modern standards

• It is safe, but there are issues around the quality of the evidence

• There are questions about increased fluorosis

Does it work as a public health policy?


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The law and fluoridation

• The 1985 Water (Fluoridation) Act– “When requested by a health authority, the water supplier may,

while the application remains in force, increase the fluoride content of the water supplied by them within that area”

– Water Companies privatised• Not in commercial interest• Indemnity issues

• Water Act 2003 Section 58 (Fluoridation of Water supplies)– Clarified indemnity issues– Removed Water Companies veto– Strategic Health Authorities are required to consult with the local

population


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Involving the public

• How do we convey scientific information to the public?

• The public perception of risk

• Public acceptance of scientific information

… GM food / crops … BSE … MMR

• Who needs to be convinced?

… “middle class ‘I’m alright Jackers’ and the feckless parents”

John and Cordelia Gummer – beef is safe


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Communicating the case

“water fluoridation is still regularly interrupted by a relatively small group of individuals who use misinformation and rhetoric to induce doubts in the minds of the public and government officials”

(Armfield, 2007)

• The role of the media– Scare stories

• Public debates– Complex arguments

• Propagation of the idea of an ongoing scientific debate– Un-refereed articles– Selective use of evidence– Innuendo– Bamboozling with science

• Internet polls


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The internet, the media and fluoridation

• In an analysis of 240 recent print, radio and television articles over a one year period in Ireland, 52% were negative and only 14% positive

(www.dentalhealth.ie)

“ water fluoridation” “water fluoridation dangers”

Search Engine

For Against For Against

Google 7 9 0 20

Yahoo 5 11 0 19

MSN 8 10 1 18

AOL 6 9 0 20

Ask 3 16 0 20

(Adapted from Armfield 2007)


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The ethics of fluoridation

IN FAVOUR• Reducing risk of ill health• Protecting the vulnerable• Reducing inequalities

AGAINST• Not coercing people to

lead healthy lives• Respecting important

personal values• The requirement of

consent

We suggest the adoption of local decision making procedures that take into account the context in each area …

… ongoing monitoring and further research to strengthen the evidence base..

… policy makers and the public need to have access to clear and accurate information (Nuffield Council on Bioethics, 2007)


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Fluoridated water – food or medicinal product?

• Not regarded as a medicinal product by the MHRA

• Water is not a food until it emerges from the tap (EU directive on addition of vitamins and minerals)

• Drinking water quality regulated by UK drinking water regulators

• Fluoride policy decided by Department of Health (Eng), Scottish Executive, Wales Assembly Government, Northern Ireland Health and Social Services Board


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Devolution and fluoridationScottish Dental Action Plan

Inter sectorial / multi agency approach

Emphasis on diet

School toothbrushing as method of fluoride delivery


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Devolution and fluoridation

“Designed to smile” – £1.44M programme

Based around school toothbrushing

April 2008

“Given that it may take some time to introduce a water fluoridation scheme in Northern Ireland, an alternative, evidence based, regional prevention programme for caries in children should be developed and implemented as soon as possible”

Oral Health Strategy for Northern Ireland

June 2007


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Devolution and fluoridation

“… I have seen the benefits for myself. One reason for us putting extra money from the health budget into fluoridation is to encourage it to happen around the country … £14M of extra money is being put in to help with this.

It is a good thing for the teeth of the people of this country.”

Rt Hon Gordon Brown PMPMQs 26th March 2008

(Hansard, 2008)


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Current public consultation Southampton PCT


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Conclusions

• Does fluoridation prevent dental caries?– Is it coincidence that in the most recent

BASCD survey, six of the ten the PCTs with lowest levels of tooth decay in the U.K. are fluoridated?

• Does it work as a public health policy?– The outcome of current consultations are

awaited with interest


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fluoridation – does it work

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