Water fluoridation international update
Currently, an estimated six million people benefit from drinking water in England, which has either natural or adjusted levels of fluoride to around one part per million. Globally, 370 million people benefit from water fluoridation schemes, including a massive expansion in the last 10 years.
In the USA alone, about 200 million (more than 70 per cent) of people drink fluoridated water, as do about two thirds of New Zealanders, Australians, Irish, Chileans, Malaysian and all of the inhabitants of Singapore and Hong Kong (see table one for the full list).
A recent study from Denmark, which combined comprehensive national data on tooth decay and fluoride levels in water, confirmed previous findings of an inverse relation between fluoride concentration in the drinking water and dental caries in children (Kirkeskov et al 2010). The caries preventive effect was reported in both primary and permanent teeth and at a level of fluoride of around 1 mg/litre (1 ppm), a reduction of approximately 50 per cent was found. So, in a modern western European country, water fluoridated at 1ppm still halved tooth decay in children in permanent and deciduous teeth.
These results are pretty much exactly in line with systematic reviews confirming that water fluoridation is effective. However, a more interesting quote is: “This correlation was found in spite of the extensive use of fluoridated toothpaste and caries–preventive prog–rammes implemented by the municipal dental services in Denmark.”
For those who might suggest that the Danish study was looking at natural fluoride, not added compounds, so is not relevant, can read the recent European Union Scientific Committee on Health and Environmental Risks Report; a critical review of any new evidence on the hazard profile, health effects and human exposure to fluoride and the fluoridating agents of drinking water, published in May 2011. It concluded that “these compounds are rapidly and completely hydrolysed to the fluoride ion”. So fluoride is fluoride, regardless of the source.
The conclusions of the Danish study confirm results found in both the systematic reviews of water fluoridation and the Cochrane review of fluoridated toothpaste (Marinho et al 2003) that the preventive benefits of fluoride toothpaste and water fluoridation are independent. They are complementary, not mutually exclusive.
A new and innovative study using intra oral photographs, comparing 12–year–olds in fluoridated Newcastle and non–fluoridated Manchester gave results which “support existing work suggesting water fluoridation together with the use of fluoridated dentifrice provides improved caries prevention over the use of fluoridated dentifrice alone.” It continues: “The social gradient between caries and deprivation appears to be lower in the fluoridated population compared to the non–fluoridated population, particularly when considering caries into dentine, demonstrating a reduction in inequalities of oral health for the most deprived individuals in the population.” (McGrady et al 2012).
In April 2013, NHS England was established to ensure that the NHS delivers better outcomes for patients, and the new local Clinical Commissioning Groups (CCGs) will commission the majority of NHS services for their populations. Is this a possible way that water fluoridation could be developed for the benefit of the wider population?
From April 2013, oral health needs assessments are part of joint strategic needs assessments (JSNAs). NHS England is expected to work with local authorities and Public Health England to develop and deliver oral health improvement strategies and commissioning plans specific to the needs of local populations (NHS Commissioning Board 2012). One major change is that local authorities will be responsible for commissioning surveys of dental health and improving the oral health of their populations. Local authorities in England now have a statutory responsibility for dental health and should come to realise that water fluoridation is effective and safe in preventing tooth decay, and will reduce dental health inequalities.
Further evidence now also shows that water fluoridation provides dental benefits that extend into adult life. Griffith’s review from 2007 showed adults with lifelong residency in a fluoridated area had a reduced Risk Ratio of carious teeth with an overall relative risk ratio = 0.65. (95 per cent confidence interval [CI]: 0.49–0.874); this is a prevented fraction of 27 per cent. A very recent paper showed that the benefits of water fluoridation to adult dental health with 11 per cent fewer DMF teeth in a nationally representative sample of Australian adults (Slade et al 2013).
Is there the political will to introduce water fluoridation more widely in England? Again, evidence from Queensland, Australia confirms that political activity can work. In 2002, only 5 per cent of the Queensland population enjoyed the benefit of water fluoridation. After the launch of a petition supported by the Australian Dental Association of Queensland, more than 25,000 Queenslanders supported fluoridation and in 2008, introduced legislation to extend fluoridation to 90 per cent of the population by 2012.
There was a statutory duty to fluoridate water supplies to more than 1,000 people and by 2011, 92 per cent of the Queensland population were already covered. Just as the ban on smoking in public places was successfully enacted across the UK, to measurably benefit the health of the nation, political action over water fluoridation may be the next public health success.
About the author
Colwyn M Jones is a consultant in dental public health for NHS Health Scotland and honorary senior lecturer with the University of Edinburgh. The views and opinions expressed in this article are solely those of the author.
Griffin SO, Regnier E, Griffin PM and Huntley V. Effectiveness of Fluoride in Preventing Caries in Adults. Journal of Dental Research 2007;86;410-415
Kirkeskov L, Kristiansen E, Bøggild H, von Platen-Hallermund F, Sckerl H, Carlsen A, Larsen MJ and Poulsen S. The association between fluoride in drinking water and dental caries in Danish children. Data from health registers, environmental registers and administrative registers. Community Dent Oral Epidemiol 2010; 38: 206–212
Marinho VCC, Higgins JPT, Logan S and Sheiham A. Fluoride toothpastes for preventing dental caries in children and adolescents. The Cochrane Database of Systematic Reviews 2003, Issue 1
McGrady MG, Ellwood RP, Maguire A, Goodwin M, Boothman N and Pretty IA. The association between social deprivation and the prevalence and severity of dental caries and fluorosis in populations with and without water fluoridation. BMC Public Health 2012, 12:1122. doi:10.1186/1471-2458-12-1122
NHS Commissioning Board (2012) Securing excellence in commissioning primary care. Leeds: NHS Commissioning Board. SCHER 2011. Accessed 14/5/2013. http://ec.europa.eu/health/scientific_committees/environmental_risks/docs/scher_o_139.pdf
Slade GD, Sanders AE, Do L, Roberts-Thomson K and Spencer AJ. Effects of fluoridated drinking water on dental caries in Australian adults. Journal of Dental Research. 2013 Apr;92(4):376-82.