Fluoride – is risk assessment up to scratch?

Fluoridation of drinking water is mired in controversy, and many people wonder why, as our biggest cities, Wellington and Auckland, have been fluoridated since the 1960’s.

Like any controversy, the issues can be difficult to pick apart, so the perspective here reflects one position.

Last Monday August, 26, Tauranga City Council (TCC) voted to seek an extension to defer the fluoridation of Tauranga’s water supply after council staff prepared a report.

Along with Dr Alanna Ratna and Robert Coe, I presented on behalf of the Physicians and Scientists for Global Responsibility New Zealand (PSGRNZ). I emphasised the absence of formal risk assessment, and that a review where the methods of analysing and assimilating information had not been disclosed – created an evidence base that was not fit for purpose. Policy-relevant science requires good process, so that it is trustworthy. This is to eliminate as much as possible, risk of predetermination or bias.

I stated that ‘risk assessment is not a departure from the science, but being true to science.’

This information did not make it into the Bay of Plenty Times news release.

Judges are rather tired of court cases brought by groups attempting to prevent fluoridation (here and here and here). Most recently, although the Director-General (D-G) was found to have failed to consider the Bill of Rights Act, the judge decided that there was no need to halt fluoridation of drinking water while the D-G reconsidered. A different and following court case, taken because the D-G had not reconsidered,  ended with the applicants having to pay $40,000 in court costs. Costs serve as a chilling effect to reduce the prospect of future court action.

We might ask whether Section 116E in the Health Act 1956 deserves some serious scrutiny. In our presentation to TCC, PSGRNZ wondered whether s116E was ‘terribly drafted’. S116E, which gives the D-G her powers, has a low evidence bar. The D-G ‘only’ has to believe that fluoridation might lower the prevalence and severity of dental caries. No requirement to balance benefit of perhaps a claimed reduction of a few caries – with cognitive neurodevelopmental risk (IQ) loss or other risks, such as too much fluoride in children’s bones. There is no requirement for the D-G to consider the safety of fluoride.

When the D-G considers whether fluoridation is a reasonable limit on the right to refuse medical treatment, does the D-G have any guidance or support to judge uncertain risks to children, and the need to take into account precaution if it’s written out of this legislation?

The entire function of the Ministry of Health demands that officials protect health. Public health is ‘the art and science of preventing disease, prolonging life and promoting health through the organized efforts of society’. The presence (or not) of expert communities shape how uncertainty is approached.

Without having to assess safety using transparent methodological processes, to ensure trust in ‘science’, without having to balance a claimed health benefits with health risks ( in the legislation, the [iii] financial costs and savings consideration doesn’t encompass broader health-based trade-offs), this new legislation, with its big fines, could undermine the obligation of both the Ministry of Health and territorial authorities to protect health by writing out uncertainty and risk.

Then there are the long haulers, towns whose municipal water has been fluoridated for decades. I’ve just asked Auckland Council whether they’ve received legal advice to understand whether s116E risks undermining or contradicting other relevant legislation.

The fines might have a perverse chilling effect where officials fail to consider other equally important legislation. These other laws form a kind of safety net, supporting officials to take safety seriously, so as to protect health (remember, safety is not in s116E) no matter the narrow interest or focus of one group.

Protecting health involves assessing competing hazards

Protecting public health includes making policy to prevent harms, and paying particular attention to the developmental origins of health and disease.

The controversy surrounding fluoride concerns fluorides’ recognised toxicity and when harm might start to happen to developing brains. Fluoride is not a nutrient. Healthy teeth depend on a wide range of minerals and trace elements, and limited access to sugar sweetened beverages and ultraprocessed foods.

Does fluoride present an unreasonable risk to developing brains? This month the most thorough study ever undertaken on fluoride and IQ risk to developing brains was released by the National Toxicology Program (NTP) in the United States. All processes – as methodology – were transparent and trustworthy.

The scientists stated that they had moderate confidence that fluoride was a developmental neurotoxin above levels dosed into drinking water (above 1.5 mg/L of fluoride), but that ‘uncertainty remains in findings at the lower fluoride exposure range’.

The study and peer review took years. When the NTP scientists conducted an updated literature search, they found that newer research with similar study designs has ‘similar patterns of findings’. What does this mean? The information on risk to kids’ IQ is unlikely to be contradicted – it is more likely to grow.

The NTP scientists expressed concern that other exposures, such as toothpaste, might cumulatively increase IQ risk. This is the problem – we cannot know when harm starts, we are all different.

The greatest intake of fluoride by bodyweight is for babies and children. In utero and 8-year-olds will have the greatest exposure, and they are the exact group for which an excess of fluoride presents the greatest cognitive neurodevelopmental risk – risk to IQ.

This is why globally, topical treatments are preferred, ‘given the optimal risk-benefit ratio’.

How does New Zealand regulate fluoride, and how do authorities assess risk from fluoride exposure?

The role of the NZ EPA, RMA & Local Government Act

Risk assessment by the New Zealand Environmental Protection Authority (NZEPA) under the Hazardous Substances and New Organisms (HSNO) Act 1996 is in place to protect the public and to the environment from harmful toxic chemicals. The NZEPA have a responsibility to protect the environment, and the health and safety of people and communities, and must take precaution into account when making decisions.

The NZEPA have never undertaken a formal risk assessment of fluoride or the fluoride compound added to drinking water. Fluoride isn’t simply added as a clean medical-grade chemical element, the liquid that is added is hydrofluorosilicic acid (HFA).

Risk assessment undertaken by independent experts in toxicology and endocrinology looks at many factors, including reproductive and developmental risk and requires officials to follow rigorous and transparent processes when selecting data. The U.S. fluoride and IQ study followed a rigorous protocol and transparently declared the way they evaluated scientific studies for quality.

When we are dealing with risk to IQ, it’s critical that authorities don’t carve out scientific information, if it contradicts their existing beliefs. Officials should not take a predetermined approach to policy-making, this is a principle of public law.

Local Communities

Local communities have historically had the power to decide whether drinking water was fluoridated in their town. Towns that are fluoridated have all municipal water dosed with fluoride. Municipal water is emitted into the environment. Authorities are required to safeguard the life-supporting capacity of water. However, in the decades that fluoride has been dosed into water, there has never been monitoring nor surveillance undertaken to identify the risk to both invertebrates and vertebrates over time.

Wastewater treatment plants don’t appear to require a resource consent to emit fluoride or HFA into rivers or the ocean.

Local authorities are stuck between a rock and a hard place. They have responsibility for the safety of drinking water and waste treatment services. Central government has had a policy of increasing immigration and tourism but have failed to commensurately support improvements in this area. The Local Government Act (LGA) 2002 promotes the accountability of local authorities to their community. When local authorities are assessing drinking water services they must ‘identify and assess any other public health risks relating to the drinking water services supplied to the community’ s125(f).

The LGA states that a bylaw may be made for the purpose of ‘protecting, promoting, and maintaining public health and safety’ (s245(a)) and that ‘the Crown is bound by any bylaw if non-compliance with that bylaw by the Crown would be likely to have an adverse effect on public health or safety’ (s153(3)).

Local communities have been able to demonstrate that the science on the fluoridation of drinking water is not settled, and that there is much uncertainty about the safety of fluoride. Being able to converse and discuss the uncertainty about fluoride’s toxicity and the need for precaution has been an important element of community participation and trust in decision-making.

New Zealand – Our evidence base

In 2014 Professor Paul Connett travelled New Zealand, presenting to local councils and to some members of Parliament. Auckland councillors consequently made a request to review the scientific evidence on the efficacy and safety of water supplies.

During this time the question of fluoride as a medicine with a therapeutic purpose was raised in a court case. The judge equated fluoride (a non-nutrient) with an essential nutrient, iodine.

In 2014 Peter Gluckman and David Skegg authored the report Health effects of water fluoridation: A review of the scientific evidence. This review cannot be considered a risk assessment. It was not undertaken by independent toxicologists, the methodology was not declared, and there was no explanation why certain studies were excluded. Later that year, an amendment to the Medicines Regulations 1984 were proposed.

But it is apparent that the courts have not twigged that the role of risk assessment is an important administrative law convention. These reviews, to all appearances, held up as authoritative by the courts, and by the Ministry of Health as gold standard, are instead more akin to fool’s gold. Both reviews lacked a transparent, methodological process for selecting which science would be deemed authoritative.

The D-G cites a 2015 Cochrane Review as more evidence. This review did not consider cognitive neurodevelopmental risk and neurotoxicity. Later that year Sapere Research Group were contracted to considered the benefits and costs of water fluoridation. This group did not review the toxicity and neurodevelopmental risk in this document nor in a later 2016 paper.

In 2021 the Office of the Prime Ministers Chief Science Adviser (OPMCSA) released a paper, which was later updated. As with the 2014 paper, there was no methodology released to demonstrate that an independent review of the scientific literature was undertaken. The peer reviewers were overwhelmingly experts in oral and dental health with a long history of favouring fluoridation.

Over this period the United States National Toxicology Program (NTP) was reviewing a broad range of studies to evaluate fluorides impact on learning and memory, and by 2020 a draft monograph had been published. Many of these were out of scope in a similar Australian review. The Australian review considered fluorosis the greatest risk and did not consider intelligence suitable as a biomarker.

Cumulative exposures should be taken into account when dosing with any medical compound.

In 2018 a New Zealand report showed that young children had higher urinary levels than adults. The main controversy revolving around the NTP draft monograph concerns the refusal of scientists involved to confirm that levels in drinking water, i.e. below 1.5 mg/l were not a cognitive neurodevelopmental hazard, in part because of other exposures, including via toothpaste.

In 2017 a case commenced in the United States under the Toxic Substances Control Act 1976, while in New Zealand oral health scientists released the paper The costs and benefits of water fluoridation in New Zealand. The latter paper stated that concerns relating to cognitive risks are neither ‘realistic nor significant’.

The OPMCSA 2021 paper did not comment about children having higher urinary levels of fluoride than adults. The NTP information was broadly dismissed as not suitable for policy development, and recent comments in a U.S. court case by an Environmental Protection Agency fluoride expert were ignored.

New Zealand – Changing our laws to require community fluoridation

In March 2016 a regulatory impact statement (RIS) was published, transferring decision-making to district health boards. The RIS did not discuss the potential for cognitive neurodevelopmental risk.

The 2016-2017 Health (Fluoridation of Drinking Water) Amendment Bill 208-2 stalled in select committee. The Select Committee dismissed submitters concerns about the safety of fluoride as ‘these issues are beyond the subject matter of the bill, which is about giving DHBs the power to make a direction about fluoridation’.

Our water services regulator is required to ‘protect and promote drinking water safety and related public health outcomes’, while the Water Services Act 2021 requires that safe drinking water is supplied to communities, and that our regulatory framework is consistent with global best practice. The Act requires that officials consider ‘other causes together with the consumption or use of drinking water’.

The Health (Fluoridation of Drinking Water) Amendment Bill was reopened and preceded by a June 1 2021 Supplementary Order paper, shifting power to the Director-General of Health to direct a local authority to add fluoride to water supplies.

One day later the OPMCSA released the 2021 paper. The timing evidentially political, as this document supported the pre-existing view of fluorides’ safety. The experts were exclusively oral and dental health experts.

An Inquiry into the Supplementary Order Paper commenced, and the August 2021 Report of the Health Committee replicated the precedent set by the 2016-2017 select committee process by refusing to comment on public concerns regarding the scientific uncertainty over the cognitive neurodevelopmental toxicity of fluoride. The Bills Digest, a repository for information relating to a new parliamentary Bill did not contain information demonstrating the government had considered the cognitive neurodevelopmental risk, with the only side effect considered being fluorosis. The RIS was not updated, with officials relying on the 2016 version to justify fluoridation of water.

The Health (Fluoridation of Drinking Water) Amendment Act 2021 then came into force. It did not mention that the full compound would be added to municipal water, simply that ‘fluoride’ would be added, which is surprising for legislation that depends on fine details. The Act does not require independent toxicological assessment of the safety of fluoride by age and developmental status.

The Act states under section s116G that officials are ‘not required to consult on any matter related to the direction or invitation.’ This contradicts the Local Government Act 2002, where officials are required to consult. We might ask if the LGA which specifically states that the Crown cannot over-ride local by-laws that concern public health, might be relevant here.

We are left with multiple absurdities

The Crown won’t do a risk assessment, and has insisted on deferring to scientifically dubious reviews to claim the science is settled. We have watched two lots of select committees swiftly dismiss public concerns about the safety of fluoride as being out of scope because the legislation is not concerned with the scientific safety. We’ve seen judges depend on official assurances but from all appearances, fail to appreciate the importance of rigorous science and transparent methodologies to impartially establish risk from toxic chemicals and medical treatments, to consider risk pathways, by age and developmental stage.

We’ve observed the Crown overlook cumulative exposures and the fact that kids have higher levels of urinary fluoride than adults, even though drinking water suppliers must legally consider cumulative exposures. We’ve seen an outdated regulatory impact statement lock in place.

Policies demonstrating topical fluoride might be safer and more effective have not been reviewed alongside policies advocating for ingestion. The Crown has then produced legislation that only requires that cavities must be reduced rather than prevented. If a marginal reduction in cavities occurs – the same inflammation, the same health problems will arise with poor oral health, but this is ignored.

The legislation states that local councillors must do what they are told and cannot consult, even though older legislation states that they must, particularly when it comes to public health. If councils have accepted money from the Crown and started the process but then do a backflip, they have to repay the lost money.

Then we’ve seen much of the fear from elected councillors revolving around the fine if they don’t fluoridate municipal water, but then perhaps the D-G never intended to enforce the fines if councils didn’t fluoridate?

A marginal reduction in cavities is the aim – but we cannot possibly evaluate the broader risks that are over-ridden by a marginal reduction in cavities. Because two reviews by scientists seconded to the Prime Minister’s department is our ‘gold’ standard.

Image credit: LuAnn Hunt