It is a very sad day for evidence based public health in Hamilton today. Council have voted to remove fluoride from the town’s water supply, 8/13 councillors voted on the matter and 7 voted to remove the fluoride. It is also striking that councillors who served on the district health board and likely knowledgeable on the issue were directed to abstain due to a conflict of interest.
In viewing the Council Agenda is sickening to see promoted advantages/benefits lined up against promoted disadvantages with no regard as to the weight of evidence. This is no way to make decisions affecting the health of the community, especially the most vulnerable.
There is a jolly good reason that fluoride is added to many water supplies worldwide. It is because these water supplies have levels of the mineral below that which optimises oral health. The water in NZ is relatively low in fluoride and adjusting the parts per million of fluoride to 0.7-1.0ppm corrects this deficiency. The NZ Dental Association strongly support and promote community water fluoridation as do the Ministry of Health and the World dental federation . What is Hamilton Council thinking?
A NZ study found a 30% lower rate of tooth decay in five year olds residing in cities with fluoridated water (i.e. Wellington) compared with those without (i.e. Christchurch) and 40% lower rates in 12 year olds and the independent association between fluoridated water and these findings was confirmed after multivariable analysis. The differences are greater for Maori and Pacific children.
The National Health and Medical Research Council in Australia (NHMRC) carried out a systematic review of high level evidence as to both the efficacy and safety of various forms of fluoridation. The evidence for water fluoridation was the most extensive. They concluded the following on safety:
- Consistent evidence that water fluoridation can cause dental fluorosis (discolouring of teeth) however this uncommon with appropriate use of all fluoride sources
- Fluoridation at the recommended levels (0.6-1.1mg/L) may reduce rather than increase fracture risk
- There is no consistent evidence that fluoridation increased risk for cancer
- No evidence on other possible negative effects
They concluded the following on effectiveness in preventing dental caries
The existing body of evidence strongly suggests that water fluoridation is beneficial at reducing dental caries. After adjustment for potential confounding variables, McDonagh et al (2000a) showed in their systematic review that the introduction of water fluoridation into an area significantly increased the proportion of caries-free children, and decreased mean dmft/DMFT scores compared with areas which were non-fluoridated over the same time period. The findings of McDonagh et al (2000a) also suggest that cessation of fluoridation resulting in a narrowing of the difference in caries prevalence between the fluoridated and non-fluoridated populations. Only one additional relevant original study was identified in the current review and this did not change the conclusion of the existing systematic review.
The McDonagh review is summarised in the BMJ.
In contrast, the “body of scientific evidence’ produced in Hamilton claiming that fluoridation was harmful is actually largely pseudoscience or irrelevant. For example:
The report from someone called Declan Waugh is not a report on the evidence on water fluoridation but some kind of personal rant. And another study submitted as evidence of harm is a review on the effects of fluoride toxicity in areas that have very high levels of fluoride (largely naturally occurring) with the reverence exposures around 0.6-1mg/L. Utterly irrelevant to this argument.
Hamilton, you have just taken a BIG step backwards in terms of public health and caring for your most vulnerable members of the community. You ignored advice from the experts such as your own District Health Board and Medical Officers of Health