New review shows clear economic benefits from community water fluoridation


The NZ Ministry of Health has released a new review of the benefits and costs of water fluoridation in New Zealand.* Unlike most reviews I have discussed here dealing with the scientific aspects, the authors of this review say:

“we take an economist’s perspective; we look at the national cost-effectiveness and cost-benefit of fluoridation, and comment briefly on disparities.”

This perspective is, of course, important to the Ministry of Health which must invest its resources efficiently. These considerations were the prime reason the Ministry commissioned the review from the Sapere Research Group.

Readers who want to read the full report (78 pages) can download it from the link – Review of the Benefits and Costs of Water Fluoridation in New Zealand (pdf, 818 KB).

Strong evidence for benefits

The review points out that oral health is still a major issue for New Zealand. Despite considerable improvement over the last 20 to 30 years, “New Zealand remains a relatively high-caries population:”

“The ‘burden’ of the disease from dental decay is equivalent to three-quarters that of prostate cancer, and two-fifths that of breast cancer in New Zealand.”

It finds strong evidence for the benefits of community water fluoridation (CWF):

“A large body of epidemiological evidence over 60 years, including thorough systematic reviews, confirms water fluoridation prevents and reduces dental decay across the lifespan. The evidence for this benefit is found in numerous New Zealand and international studies and reports.”

Its estimates of the benefits of CWF include:

  • “In children and adolescents, a 40 percent lower lifetime incidence of dental decay (on average) for those living in areas with water fluoridation.”
  • “For adults, a 21 percent reduction in dental decay for those aged 18 to 44 years and a 30 percent reduction for those aged 45+ (as measured by tooth surfaces affected).”
  • “48 percent reduction in hospital admissions for treatment of tooth decay, for children up the age of four years.”

The review expresses this cost-saving in material terms:

“We estimate the 20-year discounted net saving of water fluoridation to be $334 per person, made up of $42 for the cost of fluoridation and $376 savings in reduced dental care. In short, there is a 9 times payoff; adjusting the discount rate from 3.5 percent to 8 percent results in a 7 times payoff.”

This estimate is “robust to significant changes in assumptions.” In fact, their “assumptions around dental costs avoided are likely to be at the lower end of what patients face.”

Quality of life benefits

Not surprisingly the review finds significant benefits of CWF to the quality of life estimates.  Interestingly, it makes the point that while most other health interventions require net health spending, the CWF benefits to quality of life arise from net cost-saving because the savings from reduced need for dental treatments are far greater than the costs of fluoridation.

I can understand the need for economists to quantify the quality of life returns on investment but can not, for the life of me, understand how they can take into account the pain and misery of children who suffer from poor dental health. The review does mention an Oral Health Impact profile which attempts to measure “patient discontent from pain, dry mouth and chewing problems.” But I suspect this goes only a short way to quantifying the personal and subjective problems arising from poor dental health.

In particular, I am thinking of the psychological and physical medium and long-term effects. Poor dental health negatively impacts the child’s schooling and must contribute to learning difficulties. This, in turn, will mean childhood poor dental health reduces a person’s future prospects in employment, adult education, social and personal relationships and general happiness.


The benefits of CWF are clear when considered in financial and economic terms and this new review presents these in a clear and convincing way. It will have an important  influence on the decision makers in the Ministry of Health, parliament and the government – especially as they discuss the new legislation required for the transfer of decision-making on fluoridation from councils to district health boards. But there are also personal and subjective benefits which are much harder to quantify to the satisfaction of economists and other bean counters. In the end, those personal and subjective benefits must bring a positive economic return to society as a whole, as well as the individual. If anything, decision makers and politicians should see that the case for CWF is even stronger than that made by the economic considerations in the review.

*Note: The Cabinet papers on the assessment of benefits from fluoridation and the upcoming legislative changes required to transfer decisions to District Health Board have also been released. These papers are very interesting and give an idea of the different factors the government has considered and the likely way the new legislation will go. I recommend any readers searching for more details on this to download the papers from this link:


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17 responses to “New review shows clear economic benefits from community water fluoridation

  1. soundhill1

    No mention of minorities. I grew up in Christchurch and had one filling till I went to live fluoridated Wellington at age 28 for 3 years and started getting lots from that point.


  2. soundhill1

    sorry age 24


  3. soundhill1

    And I also started to be exposed to fluoridated water for a few hours a day in Waimairi County at age 21 and 22, sorry.

    And teh Spere report is not complete unless it menitons such things as higher costs of more specialised dialysis machines required in fluoridated areas, or the perception people have of fluoridation causing them to buy bottled water and the cost to the global warming budget. Failure.


  4. You are typically, and desperately, straw clutching again, Brian.

    I have already pointed out aspects which lead to underestimation of the benefits of CWF – inevitable as it is extremely difficult to quantify the long term cost to the community of the damage done to children by tooth decay.

    if people are silly enough to be taken in my the propaganda of the “natural”/alternative health industry then that cost is personal – it is not social.


  5. soundhill1

    “if people are silly enough to be taken in my the propaganda of the “natural”/alternative health industry then that cost is personal – it is not social.”

    Wrong, Ken. The global warming budget of water bottles impinges on the whole world.


  6. And, Brian, that expense should be put firmly at the door of the “natural”/alternative health industry who are spreading all the misinformation and fearmongering.

    In fact, you bear some responsibility for that yourself. 🙂


  7. soundhill,

    Well, if you are silly enough to be taken in by the anti-fluoridationists and buy your CWF free “natural” water in plastic bottles, that’s your own decision.

    I’ll take the tap water in a cup or glass (and have aluminium containers when tramping).


  8. Hi Ken, another great piece. Jonathan Broadbent’s work will continue to build on the quality of of life issues associated with fluoridation. As you know, he has already been the principal author behind the finding from the world famous Dunedin longitudinal study confirming there is no link between fluoridation and IQ. He has in fact also produced an award-winning report presented to last year’s US conference of the Association for Psychological Science that showed growing up in a fluoridated area actually improves a child’s development overall by reducing the burden of decay. But it has yet to be written up more fully for publication; hopefully that’s now well underway.


  9. aprilgreenlaw could you please find out where the 99 controls got their water and any difference between the high nitrate Mosgiel people and non-Mosgiel control people, please?


  10. soundhill,

    If those answers are so important to you, then I suggest that you find out for yourself. Don’t ask others to do the job for you; I suspect that you would never be satisfied with the answer anyway.

    If the answer requires scientific research then be sure to write up the research and submit it to a peer reviewed journal.


  11. Brian Soundhill is simply carrying out his task of casting doubt.

    It gets pretty childish in his case but the process is well understood. It’s used by the fossil fuel industry against the science of climate change. it was used by the tobacco industry against the science showing the dangers of smoking.
    The technique is well described in The Merchants of Doubt

    And, of course, it is used by the “natural”/alternative health industry against vaccinations and community water fluoridation. Brian has made clear his alignment with that industry.


  12. No worries, perhaps Brian would like to watch the documentary series about the study on TV one or on demand to see just how highly regarded and ground breaking it is. It doesn’t need me to speak up for its integrity.


  13. Yes, he should watch that – he can see it on TV On Demand if he didn’t record it.

    I am recording the series and am looking forward to watching ti.


  14. soundhill1

    April: “It doesn’t need me to speak up for its integrity.”

    Sometimes “integrity” means you have not disturbed anyone. Sometimes it means you had to disturb the status quo. Sometimes it means we will not give out data so as not to expose the subjects. It ought to include thinking in to the process and being very persuasive about getting money for public good research that is not going to pay anyone, or subscribe to political policy.

    I know I would not be allowed access but I would like to know if the study can say anything the tails of the distribution of affect of nitrate on iodine metabolism, to improve on current assumptions or estimates which may be averaged over a population.

    I feel it is most unfortunate that policy does not tend to allow for tails of a distribution. With regard to noise deafness the legal limit is 85dB for an 8 hour day in industry, (not allowing for music listening pleasure after work.) That level is set by allowing a certain fraction of people to begin to have difficulty understanding speech over the years. So it is not allowing for people who may be interested in listening to distant bird song.

    I read an article in “The Press” recently about the study. There will be an MRI project. The controller wrote of learning lots about the matter. Now would be the time to find whether MRI has no effect across the wide range of participants in the study. Mammals and birds have magnetic receptors. What may be the effect of the strong fields on those? IQ has been found a long time ago not to be consistently affected but only at 0.15T. The modern machines are 10 times stronger. What happens to our bio-ferrites? This long study would help to see embarassing effects otherwise missed. Then there is the noise they can make. What will be the range of (temporary) hearing threshhold shifts. For some people it may be the largest sound dose they have had.


  15. soundhill1

    April: “No worries, perhaps Brian would like to watch the documentary series about the study”

    I found this and perhaps someone might comment on my attempt at statistical analysis and my caution of the amount of blame Poulton is aiming at single parenting:


  16. soundhill,

    “I would like to know if the study can say anything the tails of the distribution of affect of nitrate on iodine metabolism”. (sic)

    No, the Dunedin study can’t say anything about that, if I managed to understand what you were trying to say. It was never part of the research.

    Sounds like a great research project for you to do. Go ahead and do the science. I’ll wait for your results to be published in a peer reviewed journal.


  17. soundhill,

    Perhaps you should read you own comments before posting. It’s very difficult to follow the way your ideas fly at the best of times. It’s even worse when you write sentences such as the one I copied/pasted in my comment above.


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