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.

Conclusion

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:

DECISION-MAKING ON THE FLUORIDATION OF DRINKING-WATER SUPPLIES.

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