Advice to the Chair of the Health Committee regarding water fluoridation. Prepared by the Ministry of Health, August 2010.

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1 Advice to the Chair of the Health Committee regarding water fluoridation. Prepared by the Ministry of Health, August Introduction Health Committee has requested information on the positive and negative effects of adding fluoride to public water supplies. This paper presents a summary of the Ministry of Health's opinion on these issues. Further information can be provided on specific points if required. This paper is in two parts. Part 1 provides some background to water fluoridation policy. Part 2 directly addresses the questions raised by the Committee. PART 1: BACKGROUND TO WATER FLUORIDATON POLICY Water fluoridation is the controlled addition of a fluoride compound to a public water supply to increase its natural fluoride concentration to a level that will best prevent dental decay while minimising the risk of dental fluorosis. Two units are often used for expressing the fluoride concentration in drinking water; parts per million (ppm) and milligrams per litre (mg/litre). The numerical values are the same in both measuring units; that is 0.7 ppm is the same as 0.7 mg/litre. Water Fluoridation in the international context The relationship between fluoride levels in the drinking water and dental decay was established in the early 1940s in the United States where water fluoridation programmes subsequently began. These early programmes resulted in a reduction in decay among children of around 50 percent. Water fluoridation has since extended to many countries, including countries New Zealand likes to compare itself to such as Australia, Canada, Ireland, the UK, and the USA. An estimated 355 million people worldwide have artificially fluoridated water. In addition at least 50 million live in countries where water is naturally fluoridated to recommended levels. In some areas, notably parts of Africa, China, and India, natural levels of fluoride exceeds recommended levels1. Fluoride has been crucial in strategies to prevent dental caries for the last 60 years. The World Health Organisation (WHO), the FDI World Dental Federation and the International Association for Dental Research have confirmed that universal access to fluoride for dental health is a part of the basic human right to health. The World Health Organization recommends that where possible, countries fluoridate their water supplies to provide the benefits of fluoride across whole communities. The United States Surgeon General stated in 2001 "Fluoridation (of water) is the single most effective public health measure to prevent tooth decay and improve oral health over a lifetime, for both children and adults"2. Furtherrnore, the US Centers for Disease Control and Prevention selected water fluoridation as one of the ten great public health achievements of the 20th century2 Ministry policy on Water Fluoridation The Ministry of Health endorses fluoridation as a safe, effective and affordable way to prevent and reduce tooth decay, especially for those populations most at risk of decay. Fluoridation of water supplies is strongly recommended where technically feasible. In the New Zealand context, the optimal level of water fluoridation is set at between 0.7 and 1.0 parts per millions. The level is set at a point that aims to provide demonstrable benefit, while minimising the risk of fluorosis a known side effect. British Water Fluoridation Society, 2001, One in a Million the facts about water fluoridation 2 Department of Health and Human Services Public Health Services Optimal levels differ slightly between countries, and may reflect differing climate and other influences. New Zealand's optimal level is generally lower than those used in the United States.

2 Positive and negative effects offluoridation, cont 'd The Ministry's policy position is based on the collective and cumulative international evidence supporting its efficacy, safety and cost effectiveness (discussed further in Part 2). Technical aspects of fluoridation The optimal level of fluoride in fluoridated drinking water ( mg/litre) is expressed as a range to allow for minor day to day fluctuations in the fluoride level. (actual concentrations of fluoride average around mg/litre in fluoridated areas and around 0.15 mg/litre in non fluoridated areas4). A maximum acceptable level puts an absolute limit on the amount of fluoride in the water at 1.5 parts per millions. These levels are set out in the New Zealand Drinking Water Standards. The Standards focus on defining safety standards to prevent adverse health effects. Fluoride levels are regularly monitored. Limited funding is available to assist Councils with the costs of fluoridation equipment. Counciis use feeder and pump systems designed for either powder or liquid forms of fluoride. In New Zealand, fluoride for water treatment is supplied as sodium fluoride, sodium silicofluoride or hydrofluorosilicic acid. Some is manufactured locally and some is sourced overseas. Whatever the source or the form, the fluoride has to meet strict quality and purity standards. Once diluted, the added fluoride acts in the same way as naturally occurring fluoride. Legislative basis Through their Crown Funding Agreements, District Health Boards (DHBs) are funded to support and promote water fluoridation in their regions. DHBs can provide advice to local Councils who may be considering whether to begin or cease fluoridation in their communities. Decision making over water fluoridation rests with local authorities. There is no specific statutory authority that covers fluoridation, but provisions in the Health Act, Food (Safety) Regulations, and Local Government Act oblige local authorities to improve public health, be responsible for water quality and consult with communities in their decision making. Approximately 89% of the New Zealand population has access to a community water supply; of those approximately 61% receive fluoridated drinking water. Therefore, around 52% of the population has access to fluoridated water, mostly concentrated in larger urban areas of the North Island (see attached map in Appendix 1). In the Ministry's view, Councils are often not well placed to consider this issue. Many Councils rely on referenda and through this process can be prone to lobbying that may not accurately reflect community views, and does not accurately reflect the science and give due regards to the relative health benefits and risks around the issue. PART 2: POSITIVE AND NEGATIVE EFFECTS OF WATER FLUORIDATION Tooth decay and the role of fluoride Dental decay is a process in which the hard mineral structure of teeth is dissolved by acids produced by bacteria in dental plaque. High sugar intake leads to both an increase in the number of decay causing bacteria and destructive acid formation. Dental decay progresses along a continuum reflecting the degree of demineralisation of the tooth structure. In its early stages dental decay can be prevented and even reversed, through the use of fluoride. If dental decay progresses unchecked, the process becomes irreversible and chronic, and results in a cavity on the crown of the tooth or a softening of the root surface. 4 Food Standards Australia report Maximum acceptabl e values are derived from World Health Organization drinking water guidelines. 2

3 Positive and negative effects offluoridation, cont 'd Once a cavity has formed, a filling or other restoration is needed to restore the form and function of the tooth. If decay is left untreated pain and infection may occur and the tooth may ultimately be lost. The protective action of fluoride on teeth is well documented. The substantial decline in caries among children in economically developed nations since the 1960s and 1970s has been largely attributed to the various uses of fluoride. Fluoride acts both topically and systemically, It helps to: Make teeth more resistant to decay by strengthening the tooth surface Interfere with the growth of bacteria that causes cavities Repair the early stages of tooth decay. Fluoride can be supplied in several forms, which may be complementary, including toothpastes varnishes, gels or sealants tablets water 6. Fluoride ingested and applied topically, such as in drinking water and brushing teeth with a fluoridated toothpaste, go hand in hand as effective measures to help prevent tooth decay. Sugar intake constantly flowing past teeth needs to be balanced by good levels of fluoride in plaque and saliva to be the 'first line' in tooth decay prevention. Positive Effects of Water Fluoridation The key benefit of water fluoridation at optimum levels is that it reduces the occurrence and severity of tooth decay across the whole population that has natural teeth. When fluoride is ingested regularly as teeth are developing, it is deposited across the tooth's entire surface making teeth more resistant to dental decay (the systemic effect). The constant washing of teeth with fluoridated drinking water helps prevent bacterial growth and rebuilds tooth surfaces (the topical effect). Because of this, tooth decay in fluoridated areas progresses more slowly. There is also increasing evidence that fluoride is especially effective in preventing decay of root surfaces. When root surfaces become exposed in older people they become vulnerable to decay, with the risk being even greater in those whose salivary flow has diminished. The use of fluoride to prevent dental decay is therefore beneficial to young children and adults alike, it also reaches those least likely to use other forms of fluoride, or to have regular dental check ups, in a way that is very cost effective and does not require any behavioural change International fiterature There are many studies evaluating different aspects of water fluoridation. Systematic reviews are of particular importance because they rigorously review a wide range of information; assessing the quality of reports, comparing methods and results, noting where consensus and controversy exist and making judgements as to the overall weight of scientific opinion. Four international reviews in recent years are of particular importance. They include: A Systematic Review of Public Water Fluoridation by the University of York ('the York Review'), 2000 The US Taskforce on Community and Preventive Services, 2002 The National Health and Medical Research Council (NHMRC) of Australia Systematic Review on the Efficacy and Safety of Water Fluoridation, in a small number of countries, such as Switzerland, France and Germany, fluoridated salt is widely used as an alternative to water fluoridation.

4 Positive and negative effects offluoridation, cont 'd Scientific Committee of the European Commission preliminary opinion on the health effects and harms from fluoridation, York Review The York review found that much of the research was of low quality and it recommended that future research should be carried out with appropriate methodology to improve the quality of the existing evidence base. Since then much more attention has been directed at implementing properly designed and credible studies. The best available evidence suggested that fluoridation reduces caries prevalence, both as measured by the proportion of children who have no decay and by average severity of decay. The degree to which decay is reduced, however, was not clear from the data available. The authors estimated that an average of only six people need to receive fluoridated water for one extra person to be decay free. It also noted that the best available evidence from studies following withdrawal of water fluoridation indicates that decay increases. The risk of fluorosis was noted, but the weight of evidence did not support claims that water fluoridation is causally related to bone fracture, cancer or other possible negative effects. The US Taskforce This report found that in spite of difficulties of comparison, the studies it reviewed supported the conclusion that water fluoridation reduced tooth decay by percent compared to those without fluoridation. Other studies showed that stopping fluoridation would be likely to lead to an average 17 percent increase in decay where other sources of fluoride were inadequate. The Task Force issued a strong recommendation that water fluoridation be included as part of a comprehensive population based strategy to prevent or control tooth decay in communities. NHMRC report This report reviewed papers published since 2000 and found no evidence to change the view that water fiuoridation is safe and effective. It concluded fluoridation of drinking water remains the most effective and socially equitable means of achieving community wide exposure to the caries prevention effect of fiuoride7. European Commission Earlier this year a scientific committee of the European Commission called for comment on its draft opinion considering the risks and benefits of fluoridated drinking water. While it noted that water fluoridation is not as effective as directly applied fluoride treatments, it found that it is generally considered beneficial especially in poorer communities". A final opinion is expected later this year. New Zealand Research New Zealand research indicates that decay levels among children are 30 to 40 percent lower in areas with optimal levels of fluoride in the water. A 1994 Public Health Commission review of 15 New Zealand water fluoridation studies found almost all (13) reported significant benefits from fluoridation". The Public Health Commission also estimated that water fluoridation prevents between decayed, missing or filled teeth in the average person over a lifetime, or 7 NHMRC 2001 A systematic review of the efficacy and safety of water fluoridation. Canberra, National Health and Medical Research Council, Australian Govemment * SCHER pre consuitation opinion; "Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking watet, European Commission 2010 * Lee M and Dennison PJ, 2004, Water fluoridation and dental caries in 5 and 12 year old children from Canterbury and Wellington New Zealand Dental Journal 100(1):

5 Positive and negative effects offluoridation, cont 'd between 58,000 and 267,000 decayed, missing and filled teeth in New Zealand per yeario. Research published a decade later confirmed that decay severity was 31% lower in 5 year old and 41% lower in 12 year old children living in fluoridated Wellington than in non fluoridated Canterbury. These differences can mean the difference between retaining teeth with fillings, or losing them to advanced decay. A 2005 study of New Zealand children living in fluoridated and non fluoridated areas of Southland found that children who had lived in fluoridated areas all of their lives had half the dental decay of those who had not". Ministry of Health data also shows a consistently positive effect of fluoridated water on the level of decay among children. Māori and Pacific children on average have better oral health when living in fluoridated areas, however they are disadvantaged by being overrepresented in un fluoridated areas. Cost effectiveness Fluoridation is a very cost effective way to reduce dental decay across communities. The financial costs of treating dental disease are high, while the costs of water fluoridation are relatively low. In 1999, a group of independent scientists and economists advised that the economic argument for water fluoridation is very strong, especially for communities with lower socio economic status. In a town of around 50,000 people, fluoridation would prevent an estimated 74,200 cases of decay over 30 years. On those figures it was conservatively estimated it would cost around $4.20 to prevent each case of decay. Without fluoridation it would cost around $ to treat each case of decay". This shows that treating decay is around 30 times more expensive than preventing it with water fluoridation. Negative Effects of Fluoridation Fluoride toxicity It is impossible to experience fluoride toxicity from drinking water optimally fluoridated at levels between 0.7 to 1.0 ppm, as it would require drinking several thousand glasses of water at one time. Dental Ruorosis Dental, or enamel fluorosis is a condition of altered enamel formation caused by excessive intake of fluoride during tooth formation (fluorosis is only one of a wide range of developmental defects that can occur in tooth enamel). Fluorosis severity ranges from very mild to severe. At the very mild to mild end of the spectrum, the effects are opaque white areas or flecks in the enamel that are barely noticeable to the naked eye, do not affect tooth function and do not require treatment. Severe dental fluorosis is characterised by brown stains or pitting. It can be a disfiguring abnormality of tooth enamel, but it is not caused by water fluoridation at optimal levels~2. Many studies on fluorosis confirm that, in optimally fluoridated areas, dental fluorosis is usually only mild or very mild. A 2005 study of 9 year old children in Southland found that 29 percent of those who had always received fluoridated water had diffuse enamel opacities, including fluorosis. Importantly, the study found the level of diffuse enamel opacities among children who lo Public Health Commission, 1994, Water Fluoridation in New Zealand; an analysis and monitoring report " ESR, 1999 The Cost Effectiveness of Fluoridating Water Supplies in New Zealand, Institute of Environmental Science and Research Limited, 12 Moderate to severe fluorosis most commonly stems from excessive toothpaste consumption, extremely high natural fluoride levels or environmental pollution. There are also many other causes of defects in dental enamel

6 Positive and negative effects offluoridation, cont 'd had lived their whole lives in a fluoridated area had not increased since earlier studies in the 1980s. A study undertaken in Auckland during had similar resultst3, More recently, a nutrition risk assessment report undertaken by Food Standards Australia and New Zealand (FSANZ) observed that the prevalence of very mild and mild fluorosis was 10% to 25% in Australian and New Zealand children. This was associated with exposure frorn several sources, including fluoridated water, toothpaste, other dental products and supplement use. While the prevalence was generally higher in fluoridated than non fluoridated areas, FSANZ did not report any evidence of the more severe forms of fluorosist4. Infant formula The risk of fluorosis for children consuming infant formula made with fluoridated water was highlighted in the recent European Commission Report (one of the systematic reviews referred to above), and there has been public concern about this. The report noted the risk that recommended daily intakes of fluoride could be exceeded where fluoridated water over 0.8 parts per million is used to make up infant formula. Opponents of water fluoridation claim this to be evidence that fluoridation is toxic. However it is important to note that the risk only relates to levels of fluorosis that are barely noticeable, and do not need treatment. Recently published New Zealand Guidelines on the Use of Fluorides also considered this issue and concluded that current intakes do not constitute a safety concern". Claims of other negative effects Water fluoridation is sometimes claimed to be linked to other negative health effects, particularly bone cancers and fractures. In 2000 the Ministry commissioned an independent systematic review of evidence around water fluoridation. This included an investigation of possible harms such as fluorosis, bone fractures and cancers. While the report noted that more research was needed into bone cancer, it concluded there was no clear evidence of harmful effects associated with optimal fluoridation of water supplies, and the study generally strengthened conclusions that there are no adverse health effects associated with fluoridation16. The NHMRC report found no clear evidence of a link between fluoridation and bone or other cancers, and that there is little or no effect on risk of fractures. It reported no reliable evidence to link water fluoridation with conditions such as Down's Syndrome, allergic conditions, mutations and enzyme dysfunction". The World Cancer Research Fund noted that there is no substantial evidence that fluoride (as consumed in water or foods) has any significant effect on the risk of any cancer18. In its report, the European Commission (reference) found that water fluoridation does not impair children's neurodevelopment or [Q and that studies do not suggest adverse thyroid, skeletal, reproductive or cancerogenic effects of fluoride at realistic levels in drinking water. Fluoridated drinking water also poses no risk to the enviroment. it is important to note that many of the studies showing harmful effects of fluoride, especially around fluorosis, come from areas where natural fluoridation is very high, or in those countries with significant levels of fluoride in the environment from industry. " Schluter et al 2008, Prevalence of enamel defects and dental caries among 9 year old Auckland children New Zealand Dental Joumal 104 (4): t4 Food Standards Australian and New Zealand 2009, New Zealand Guidelines Group " Guidelines for the Use of Fluorides, New Zealand Guidelines Group 2009, p6 " ESR 2000 Fluoridation of water supplies: An evaluation of recent epidemiological evidence Institute of Environmental Science and Research Limited " in fact a slight protective effect was evident, that is, fluoride at particular concentrations appeared to reduce the risk of fracture. " World Cancer Research Fund/American institute for Cancer Research, 2001, Food, Nutrition, Physical Activity and the Prevention of Cancer: a Giobal Perspective, Washington, p150

7 Positive and negative effects offluoridation, cont'd Water fluoridation and civil liberties Confidence in access to safe water is an important issue for communities. While some individuals may regard adjustment of the fluoride level as an infringement of their choice, their viewpoint has not been supported when tested by bodies mandated to examine such issues. Fluoride occurs naturally in most waters and cannot be considered an impurity. This was confirmed by a Privy Council decision that stated "the addition of fluoride adds no impurity and the water remains not only water but pure water and becomes greatly improved and still natural water containing no foreign elements'". The Human Rights Commission found that "In aii CirCumstanCes therefore, it is Considered that the question of fluoridation of water supplies by public authorities does not Constitute a denial of human rights. "" This also addresses the concern that fluoride is a form of 'mass medication'. Fluoride is a natural element and is not a medicine. Though it has therapeutic effects, its addition to water (at optimal levels) does not change the nature of water. Summary The Ministry of Health strongly recommends water fluoridation as a safe, effective and affordable way to prevent and reduce dental decay. Water fluoridation provides protection to those most at risk of decay, particularly to children from disadvantaged families and communities. Fluoridation reduces the need for, and the cost of dental treatment. Savings accrue both to publicly funded services, and to private payers. The risk of dental fluorosis is minimised through the careful determination of optimal and maximum acceptable levels of fluoride in drinking water. Dental fluorosis levels in New Zealand have been studied and are not a cause of concern. This position is based on the collective findings of a large body of evidence spanning around 60 years. The Ministry regularly reviews the scientific literature on this subject to ensure its policy is consistent with international evidence and best practice. " Privy Council Appeal no. 25 of 1964, Her Majesty's Attorney General of NZ v the Mayor, Councilors and Citizens of the City of Lower Hutt. 20 Item no. 9, Proceedings of the Human Rights Commission, 13 August 1980

8 Fluoridated Drinking Water Supply Zones Percentage of zones by Territorial Authority N Legend D 0 25% ~ 26 50% f 51 75% ~ % Auckland ~km ikm m Chatham Islands Wellington =~ ~ km ,~ Km The Chatham Islands lie 800 km east of New Zealand. Health services are provided by Hawkes Bay DHB.