North & South
SOMETHING IN THE WATER
The water fluoridation debate has raged since
1954, with bad blood and bad science on both sides.
Debate over water fluoridation has raged since it was first trialled in New Zealand in 1954. A new book reveals how dental nurses were caught up in a rigged study to justify its introduction and were later drafted as propagandists for the programme. Noel O’hare traces fluoridation’s vexed history and looks at why misinformation and rancour persists on both sides.
This year, New Zealanders will get the chance to have their say on two controversial issues, euthanasia and cannabis legalisation. There is another contentious issue, however, that long predates these two – water fluoridation. Water fluoridation is even thornier, in a way, because those who oppose it can’t easily opt out.
For a naturally recurrent mineral already present in water, air and some foods, fluoride has attracted fierce opposition since it was first added to drinking water in Grand Rapids, Michigan in 1945. As I discovered when writing Tooth and Veil, my soon to be released book about school dental nurses, New Zealand was the second country in the world, after the US, to fluoridate drinking water. The story of that experiment, with the deceptions, misinformation, paranoia, rancour and suspicion of both sides, helps explain why water fluoridation remains highly controversial 65 years later, and why both sides are still deceiving the public.
In 1954, the Health Department engaged school dental nurses in a 10-year study on water fluoridation to demonstrate its
effectiveness in reducing dental decay. Hastings, which had already fluoridated its water, was chosen as the subject of the study, while nearby non-fluoridated Napier, with its identical water supply, was the control. After just 27 months, the Health Department was reporting “spectacular results” of a 50-60% reduction in tooth decay among Hastings children.
One person who needed no convincing about the benefits was Auckland dentist John Colquhoun, who had closely followed American studies on fluoridation. A softly spoken man with a strong social conscience, Colquhoun (who died in 1999) saw fluoridation as a way to reduce disadvantage in dental health for those living in low-income areas. As an Auckland city councillor, he was able to persuade the council to fluoridate the city’s water supply, despite fierce opposition from some fellow councillors and the newly formed New Zealand Anti-fluoridation Society.
Years later, as Auckland’s principal dental officer supervising the region’s school dental service, Colquhoun became the country’s leading advocate of fluoridation. His Health Department bosses were so impressed they sent him on a world study tour so he could become their expert on fluoridation and lead a campaign to promote the practice in those parts of New Zealand that had resisted adding fluoride to their drinking water.
Before he set out on his travels, though, health officials confided to him some unexpected data: school dental clinic records were showing children’s tooth decay was now declining at the same rate in both fluoridated and nonfluoridated areas. Nevertheless, they felt sure that when they’d collected complete data for the country, it would still show the benefits of fluoridation, albeit not the 50-60% previously claimed. The tooth decay decline in non-fluoridated areas they attributed to the use of fluoride toothpastes and fluoride supplements, and from fluoride applications to the children’s teeth in dental clinics.
As a keen fluoridationist, Colquhoun readily accepted their explanation. But on his world tour, he discovered health officials in the US, Britain and Europe had been puzzled by the same phenomenon: tooth decay was declining across the board without water fluoridation. Still, like their New Zealand counterparts, they were convinced larger-scale surveys would show the benefits.
Colquhoun returned to New Zealand still an ardent fluoride advocate and was appointed chairman of a new national Fluoridation Promotion Committee. His job was to inform the public and his fellow dentists that water fluoridation resulted in better children’s teeth. Before throwing himself into the role of chief promoter, however, he decided on further research and was shocked by what he found. In his paper “Why I Changed my Mind about Water Fluoridation”, he later wrote: “[While I was away] I looked at the new dental statistics that had been collected for my own health district, Auckland. These were for all children attending school dental clinics – virtually the entire child population of Auckland. To my surprise, they showed that fewer fillings had been required in the non-fluoridated part of my district than in the fluoridated part. When I obtained the same statistics from the districts to the north and south of mine – that is, from ‘Greater Auckland’, which contains a quarter of New Zealand’s population – the picture was the same: tooth decay had declined, but there was virtually no difference in tooth decay rates between the fluoridated and non-fluoridated places. I wondered why I had not been sent the statistics for the rest of New Zealand. When I requested them, they were sent to me with a warning that they were not to be made public. Those for 1981 showed that in most health districts the percentage of 12- and 13-year-old children who were free of tooth decay – that is, had perfect teeth – was greater in the non-fluoridated part of the district.”
Colquhoun did not dispute that fluoride was effective in reducing tooth decay when applied topically but concluded there was “negligible benefit from swallowing fluoride”. (He was not alone in that diverging finding. In his 1996 paper “Fluoridation: Breaking the Silence Barrier”, Australian research scientist Mark Diesendorf wrote: “… we find that tooth decay in Australia’s only unfluoridated major city, Brisbane, is about the same as in fluoridated Adelaide and Perth... In New Zealand, tooth decay in unfluoridated Christchurch is about the same as that in all the other major cities of that country, which are fluoridated. Similar results have been reported from the US, Canada and elsewhere. Nowadays there is little or no significant difference in tooth decay in permanent teeth between many comparable fluoridated and unfluoridated regions.”)
This presented a quandary. Colquhoun’s professional reputation had been built on fluoridation, but he could not ignore this new evidence. The argument that children in non-fluoridated areas were benefiting from fluoride in other ways no longer seemed convincing to him. He knew that in Auckland very few children used fluoride toothpaste, many had not received fluoride applications to their teeth, and hardly any had been given fluoride tablets. Examining the records of the large numbers of children who had been treated in school dental clinics from the 1930s on, he found that rates of tooth decay had started to fall well before fluoridation had been introduced, and continued after all the children had received
fluoride all their lives, so the continuing decline could not be because of fluoride. Colquhoun speculated later that the decline had been the result of the “tremendous increase in the consumption of fresh fruit and vegetables since the 1930s, assisted by the introduction of household refrigerators. There has also been an eightfold increase in the consumption per head of cheese, which we now know has anti-decay properties.”
Colquhoun also discovered that a quarter of the children in fluoridated Auckland had mottled teeth, or dental fluorosis, caused by an excess intake of fluoride. It seemed to him that if fluoride toxicity could affect tooth-forming cells, it may also affect other parts of the body. He felt he had no alternative but to resign, and took early retirement from the Department of Health. After a lifetime of advocating fluoridation, he became the poster boy for the anti-fluoridationists he had previously poured scorn on.
Now it was his turn to endure the scorn of former allies. After retirement, he acquired a PHD in the history of fluoridation and decided to have another look at the 1954 Hastings study. Using the Official Information Act, he accessed
Health Department files related to the study and was astonished by what he found. “In effect, it was a rigged experiment,” he said. School dental nurses in Hastings had been given strict instructions to change their usual method of diagnosis on what constituted tooth decay. Before the experiment, they had filled (and classified as “decayed”) teeth with any small catch on the surface, before it had penetrated the outer enamel layer. After the experiment began, they filled (and classified as “decayed”) only teeth with cavities that penetrated the outer enamel layer. This moving of the goal posts brought about an apparent sudden drop in “decayed and filled” teeth among Hastings children. However, when early results were compared with the control city, it was found tooth decay had actually declined more in Napier, despite the fact that dental nurses there were using the old, more stringent method of diagnosis.
How could this be? “The claimed excuse,” Colquhoun later wrote, “was that a previously unknown trace element, molybdenum, had been discovered in some of the soil of the control city, making tooth decay levels there unusually low, but this excuse is not supported by available information, from the files or elsewhere, on decay levels throughout New Zealand.” Napier was dropped and the study continued without a control.
Colquhoun documented his findings in the paper “The Hastings Fluoridation Experiment: Science or Swindle?” Swindle it may have not been, but it was bad science.
Despite its obvious defects, the Hastings study was hailed as demonstration of the effectiveness of water fluoridation, reducing dental decay by up to 60%, and seems to have been on par with many of the early studies on water fluoridation. In the paper previously mentioned, Mark Diesendorf recalled his first encounter with the research: “When I read the original papers, I was amazed at the arbitrary selection of data and the absence of statistical analysis. The scientific standard of many of the ‘classic’ papers was that of junior high school rather than university research.”
Nevertheless, the Health Department saw fit back then to begin promoting water fluoridation without regard to any potential impact on the very young, the elderly, and those with kidney disease
or other conditions. School dental nurses were drafted as propagandists for water fluoridation. An editorial in the School Dental Gazette advised dental nurses to bring children on board with the aid of a new filmstrip called Fluoride Fairy. It “is designed for our younger age groups, introducing the subject in its true perspective as another important method of controlling dental decay. This is the starting point from which the next generation can learn to appraise its benefits through scientific facts. If all the suitable water supplies have not already been fluoridated by the time these children have a voice in community affairs, it will be too late for those who have not lived within its influence to gain very much improvement in their own dental health. With the greater appreciation of this modern approach, however, they will accept it in the same way as previous generations have come to accept the school dental nurse herself, not for themselves but for their children and their neighbour’s children.”
Despite the “scientific facts”, water fluoridation attracted vociferous opposition from such disparate individuals as scientists worried it could cause skeletal deformation and cranks who feared it would encourage left-handedness and feminism. Personal rights advocates saw it as an affront to individual liberty. In the archives, Colquhoun discovered the Health Department had asked police to find out whether communists were behind the opposition to water fluoridation (this was at the height of the Cold War).
The rancour between the two sides has never gone away. Fluoridationists dismiss opponents as scaremongering cranks, and anti-fluoridationists regard the other side as unethical authoritarians who deal in half-truths and refuse to consider any inconvenient evidence. There is some truth in each side’s accusations.
Anti-fluoridationists like to get their message across with billboards. One claimed: “Informed Dentists Say No to Fluoridation”. In fact, the vast majority of dentists are in favour of fluoridation. According to a policy statement on its website, the New Zealand Dental Association “continues to strongly support and promote community water fluoridation as a safe and effective preventative measure to improve public oral health”.
Another more recent billboard read: “New Study: Top Medical Journal – Fluoridated Water Lowers Kids’ IQS”. Although it’s true a study did appear in the prestigious journal JAMA Pediatrics, the findings have been disputed and do not justify a scaremongering billboard.
On the other side, the Ministry of Health fudges about the uptake of water fluoridation around the world. According to the MOH: “In some countries in Europe, the practicalities in adding fluoride to the water supply mean that alternative methods are used to boost fluoride to optimal health levels.” The idea that Europeans can’t work out how to fluoridate their water supplies is disingenuous. Most countries in Europe have discontinued water fluoridation because they provide high-quality dental services for children and/or prefer alternatives, such as fluoridated salt.
The statistics seem to validate that approach. The countries with the best children’s dental health in the world – Germany, Denmark, Netherlands, Switzerland, Sweden – don’t fluoridate their water. Only 11 countries have more than 50% of their population drinking fluoridated water, including Australia, the US, Singapore and Hong Kong. However, it’s also important to note that New Zealand has naturally low fluoride levels in our water, below those known to benefit oral health, while some of the European countries cited have ample naturally existing levels.
So what are we to believe about water fluoridation? The Cochrane Collaboration, regarded as the gold standard for its rigorous reviews of research literature and evidence-based medicine, recently found “the introduction of water fluoridation resulted in children having 35% fewer decayed, missing and filled baby teeth and 26% fewer decayed, missing and filled permanent teeth”, but did not find any benefits for adults. And they added a rider: “Our confidence in the size of the effect estimates is limited by the observational nature of the study designs, the high risk of bias within the studies and, importantly, the applicability of the evidence to current lifestyles.”
In 1999, the UK National Health Service commissioned York University to do a systematic review of the benefits and risks of water fluoridation. The York review concluded that on both sides of the debate, the evidence was mostly unreliable. They found water fluoridation probably resulted in only a 15% reduction in dental decay. No association was found between water fluoridation and adverse effects such as cancer and bone fracture. “However, we felt that not enough was known because the quality of the evidence was poor.” They also concluded the “evidence about reducing inequalities in dental health was of poor quality, contradictory and unreliable”.
Despite these cautious findings, the report was so badly misrepresented that Professor Trevor Sheldon, the chair of the review, took the British Dental Association and the British Medical Association to task for “misleading the public” by claiming the review had found water fluoridation to be a safe and effective way to reduce social inequalities in dental health.
According to Sheldon, the York Review concluded that “until high-quality studies are undertaken providing more definite evidence, there will continue to be legitimate scientific controversy over the likely effects and costs of water fluoridation”.
In his 2011 paper entitled “Slaying Sacred Cows: Is it Time to Pull the Plug on Water Fluoridation?”, health policy researcher Professor Stephen Peckham writes: “The key problem is there is a lack of good-quality evidence of both effectiveness and harm. This is a point consistently raised in reviews of water fluoridation. However, both proponents and opponents of water fluoridation continue to selectively draw on the evidence to support a view that water fluoridation is effective and safe or that it is harmful. A more balanced reading of the evidence is that water fluoridation has little effect, is a poor delivery mechanism, causes dental fluorosis and may have other long-term harmful health effects. It certainly does not meet… the standard
Despite the “scientific facts”, water fluoridation attracted vociferous opposition.
for evidential proof of benefit. Fluoride is effective when applied topically but is potentially harmful when ingested.”
However, more recent studies in both New Zealand and Australia reached a different conclusion. In 2014, a joint review of the health effects of water fluoridation by the Royal Society of New Zealand and the Office of the Prime Minister’s chief science advisor found “the levels of fluoridation used in New Zealand public water supplies create no health risks and provide protection against tooth decay”. And in 2017, a study by Australia’s National Health and Medical Research Council concluded water fluoridation reduces the occurrence and severity of teeth decay.
Aside from the ongoing controversy, there’s also the question of ethics. Is it ethical to fluoridate the water of an entire population when other targeted methods may be just as, if not more, effective? The UK Nuffield Council on Bioethics wrestled with this issue in 2007. It concluded that local and regional communities should democratically decide on whether or not to fluoridate their water supplies. With misinformation on all sides, though, it’s hard to see ordinary citizens being able to assess the true risks and benefits. In 2016, our National government sought to relieve them of that burden by introducing legislation that would give district health boards the power to direct local authorities to fluoridate their water supplies. The Health (Fluoridation of Drinking Water) Amendment Bill has yet to get its second reading.
Given the lack of consensus about how effective water fluoridation would be in today’s environment, and even the remote possibility of harm to young children, it would seem water fluoridation is an idea whose time has passed. People are now less inclined to accept the assurances of experts, and feel empowered by the internet with its surfeit of information, good and bad. Politicians are even reluctant to raise the issue of compulsory vaccination, despite the fact herd immunity is necessary to keep serious contagious diseases at bay. The main rationale for water fluoridation, that it would greatly reduce inequalities in dental health, is far from certain. A recent New Zealand study of water fluoridation and ethnic inequalities, based on information collected from 2004 to 2013, concluded water fluoridation was “relatively effective” and could reduce but “itself did not remove disparities in caries levels between Māori and non-māori children”.
In 2010, a study by the European Scientific Committee on Health and Environmental Risks found “topical application of fluoride is most effective in preventing tooth decay. Topical fluoride sustains the fluoride levels in the oral cavity and helps to prevent caries, with reduced systemic availability. The efficacy of population-based policies, e.g. drinking water, milk or salt fluoridation, as regards the reduction of oral-health social disparities, remains insufficiently substantiated.”
Another review concluded: “Although water fluoridation may still be a relevant public health measure in poor and disadvantaged populations, the use of topical fluoride offers an optimal opportunity to prevent caries among people living in both industrialised and developing countries.”
Water fluoridation now seems more of a tick-the-box exercise when it’s plain that much more, including a sugary food and drink tax, is needed to improve dental health, especially for disadvantaged children. Each year, thousands of children in fluoridated and non-fluoridated regions of New Zealand are hospitalised to have rotten teeth removed under general anaesthetic. Poverty and a shortage of dental therapists are two important factors in what has been called a dental health crisis.
Things are unlikely to improve anytime soon. In 1982, as school rolls declined, the government closed the Auckland and
Water fluoridation now seems more of a tick-thebox exercise when it’s plain that much more, including a sugary food and drink tax, is needed to improve dental health.
Christchurch dental nurse training schools. A year later, the creation of area health boards meant dental nurses were no longer part of a national service. Hundreds of young dental nurses were made redundant, because they were cheaper to pay out; a third of currently practising dental therapists are aged between 55 and 75. Mobile dental clinics have now largely replaced the clinics that were once in almost half of our primary schools.
Adding something to the water is not going to solve a complex social problem. But a model programme already exists that has proven effective, and generates none of the controversy surrounding water fluoridation. In 2001, Scotland, which chose not to fluoridate its water after strong opposition from the public, introduced a national dental health programme for children, called Childsmile. “There was no appetite to take the fluoridation route, but we needed to do something. So we agreed with the chief dental officer to be pragmatic,” Professor Lorna Macpherson, a director of Childsmile, told the Guardian.
Under the programme, every child attending an early childhood centre in Scotland is offered free daily supervised tooth brushing. In the poorest parts of the country, this extends into primary schools. Children also receive free toothbrushes and toothpaste and two fluoride varnish applications per year. Children get regular dental check-ups from 18 months, and parents and adult carers are given dietary advice on how to help prevent children’s tooth decay.
The BBC recently reported the latest figures for Scotland that show four out of five children “had no obvious decay experience in their permanent teeth in 2019. This is up from 53% in 2005 when records began.” The scheme is saving the National Health Service more than $10 million in treatment costs. Macpherson describes it as the more holistic approach: “The universal part, the equivalent of water fluoridation if you like, is the nursery toothbrushing. Then for the children more at risk of caries, we offer additional support. We call it proportionate universalism – something for everyone, but proportionate to their needs.”
Ironically, Scotland’s “pioneering” programme echoes what New Zealand was doing for most of the 20th century. Back in the 1950s, school dental nurses were applying topical fluoride, teaching kids about dental hygiene in the classroom, organising toothbrush drills and providing regular check-ups and treatment. No child missed out, because dental clinics were in the school grounds. However, hampered by outdated equipment, lack of anaesthesia and supervising dentists who insisted on over-treatment, the work of school dental nurses was often disparaged and the “Murder House” meme was born.
In the late 1980s, the national School Dental Service, a unique New Zealand innovation that could have been modernised and expanded to provide basic treatment to low-income adults, was abolished. But that’s another story. +