Deep research finds water fluoridation is safe, effective
I am a pediatrician in Meadville. I emigrated from Hong Kong to U.S. more than 20 years ago. I moved to Meadville because the hospital sponsored me to get my green card. My plan was to move to Buffalo once I got the green card. Two years later, I got my green card, but I decided to stay. The people here are so friendly, and it is a good place to raise kids. Meadville is my home now.
When I started seeing kids here, one thing that struck me was the dental caries problem. Initially I thought it might be related to the population that I serve. We have a lot of Medicaid patients. However, when I looked into the data, I found that we have a higher rate of dental caries than Pittsburgh or the nation as a whole (Figure 1). It is true that we do not have a dental school here and we have fewer dentists per capita, but another major difference is that we do not have fluoride in our city water.
When I was invited to be a member of the water fluoridation committee, I used my academic skill and resources to dig deep into all the data available to the public. I reviewed all the original articles in English about the effectiveness of water fluoridation in preventing dental caries from 2010 to 2013. What I found is that water fluoridation is safe and effective. There is no controversy among the scientific or medical communities. There may be individual doctors or scientists with different opinions, but any scientific or medical organization with special task forces looking into the data would endorse water fluoridation.
Now let me discuss about some of the concerns raised by those who oppose fluoridation.
Rate of dental caries has decreased significantly throughout the world since the late 70s coincident with the introduction of topical fluoride product such as fluoride toothpaste, mouthwash and varnish application by dentists. Many European countries, such as Denmark, Norway, Finland and Sweden, have a very low dental caries rate despite no water or salt fluoridation. The DMFT score of Denmark(DMFT, stands for Decay Missing Filled Teeth, a measure of the degree of dental caries, usually measured at age 12, the data is available from WHO to the public ) is only 0.6 and is the lowest among the developed countries. However, the picture is very different when you look at Eastern Europe or Asia. The Scandinavian countries are well known for their high GDP per capita, socialism and social equality. The Gini indices (a measure of income inequality) of Denmark, Norway, Finland and Sweden are among the lowest in the world. On the other hand, the US has the highest in the developed world (Figure 2). All four named countries above provide free dental care for all children under 18 and significantly subsidized care for adults. We do not have these benefits and very unlikely to have them in the future. Let us look at several countries in Asia. The DFMT score of Korea, Japan or Malaysia were much higher than the US (Figure 3). The exceptions are Hong Kong and Singapore. Both were previous British colonies and have the water supply 100% fluoridated. The most interesting example would be Hong Kong and Macau. Hong Kong and Macau are now both parts of China but under their own corresponding independent administrations called SAR (special administrative region). Hong Kong was a British Colony in the past while Macau belonged to Portugal. They are located on the opposite side of the Pearl River. They have the same ethnic origin, language, diet and same culture. Both have a GDP per capita comparable with most developed countries but have high Gini indices. Macau is richer with a lot of tax money from the gambling industry. As the result, the government can offer free health service in the government clinics. (The service is not very good and most people would use the private sector instead). However, Hong Kong has had the water fluoridated since 1962 (as ordered by the UK government, no discussion needed) while Macau never has. How about the DMFT score? Hong Kong is 0.8 and Macau 2.0(Figure 3)! Similar picture is seen in Ireland and North Ireland as well. Here is a word of caution. As a nation, Denmark has the lowest rate of dental caries with the DMFT only 0.6. But there was a study showed that in a pair of neighbor towns in Australia, the town with water fluoridation has DMFT of 0.33 compared to 0.69 of the town without water fluoridation. It is hard to say if Denmark may have an even lower rate if they have their water fluoridated.
There is a concern that fluoride may be a neurotoxin. It may harm the brain if there is fluoride in the water. Recently there is a review article published in Lancet by a Harvard professor titled ‘Neurobehavioural effects of developmental toxicity‘. He mentioned 11 chemicals as neurotoxicants and fluoride was one of them. To support his argument, he quoted only one article of meta-analysis published in 2012 by a Harvard research scientist, titled ‘developmental fluoride neurotoxicity: a systematic review and meta-analysis‘. Meta-analysis means grouping many studies together and analyzing the data. It included 27 studies, 25 from China and 2 from Iran. None were from the US or other developed countries. All were comparing IQ from very high natural occurring fluoride (around 3 – 11 ppm) areas to that of low fluoride area. Many of the low fluoride areas actually have fluoride level around 0.4 – 0.7 ppm, that is usually considered the optimal fluoridation level. Even if the data were valid, fluoride may be toxic to the brain at a very high level but not at 0.7 ppm, the level of water fluoridation. My concern is that most of the studies were published in Chinese. Usually if a Chinese scientist has a good study, he/she would try to summit to a prestigious international journal first. If rejected, he/she would try some less prestigious one. The next would be to a non indexed English Journal such as ‘Fluoride’. Go to the table of contents of the Fluoride Journal and you would see how many authors are Chinese. Only as a last resort would one submit to a Chinese language journal. This is realty. No international scientists would have the access to the Chinese journal and that means no one is going to quote your studies. Therefore, most, if not all, the studies published in Chinese are very poor in quality. People know that but they would not say it for the sake of political correctness. Only the fluoride alert network thinks that these studies are so important that they need to hire people to translate them into English. Chinese scientists have no concern for political correctness and have done studies on these Chinese studies. They found that Chinese studies in general are more likely to have positive findings, especially if they are published in Chinese (some were in the range of 90%). So it would not be a surprise that ALL the fluoride studies are positive despite the fact that some of the studies were quite small in sample size. The Harvard scientist called for more studies in this area but it is hard to say if other scientists would follow. There are areas in US, UK, Europe with very high level of natural fluoride. This was how fluorosis was discovered (first reported in UK). Why doesn’t anyone do any studies? It is very simple for the Harvard scientist (an Asian) to just go to China to replicate one of the studies using proper methodology and the answer would be clear. Other epidemiologists would have difficulty due to the language and cultural barrier (IQ test is very culturally dependent), not to mention that they would be more skeptical. No one would be interested in doing any negative studies in the US or Europe. We may never know the real effect of high levels of fluoride in cognitive function. As an anecdotal example, the PISA (Programme for International Student Assessment) of OECD (the Organization for Economic Cooperation and Development) had done evaluation of high school students in many countries all over the world. They studied thousands of children in each centers. They found that the IQ equivalent score of Hong Kong is about 5 point higher than that of Macau. Does that mean the fluoride in the water improves the IQ? Actually, it is quite plausible. There are many studies showing that dental caries has a very significant detrimental effect in learning. It would not be a surprise that the higher rate of dental caries caused the lower IQ in Macau.
Another common concern is the possibility of the link of water fluoridation and osteosarcoma. Several animal studies have been conducted but only one found that fluoride exposure may increase osteosarcoma formation in rat. In 2000, a Harvard PhD student studied the link of water fluoridation and osteosarcoma and finally published in 2006. It was a big study for a rare cancer and involved 103 patients. She found that for patients with osteosarcoma, the males have a statistically higher exposure to fluoride at the age of 7, not female, and not at other age. Since then, there were 5 more studies published. One was a case control studyof 142 patients with osteosarcoma comparing with other bone tumors in bone fluoride content. Another 4 studies were ecology studies through the cancer registry in the US, UK, New Zealand and Ireland respectively. All 5 studies did not show any association. The one study in UK involved 2,566 patients with osteosarcoma from 1980 to 2005 (25 years).The sample size was so large that the 90% confident interval for RR (relative risk) was very narrow at 0.77 to 1.12. That means it would pick up the association 90% of the time if the prevalence is just 10% more. That is a lot of technical jargon. All I want to say is that the chance of a real link between fluoride and osteosarcoma is very, very small.
Another common complaint is that there are no double blind randomized control trials in the evaluation of the effectiveness of water fluoridation in preventing dental caries. It is technically impossible to have such study done. The persons who assess the DMFT score would definitely know whether the water is fluoridated. But there is another way to assess the severity of the dental caries problem – the money used in dental procedures. Recently there was a study in New York State comparing the number of restorative, endodontic and extraction procedures per recipient between fluoridated counties and non fluoridated counties. It found that it was 33.4% more in the non fluoridated counties while there is no difference for the non dental related procedures. It translates into $23.63 saving per Medicaid recipient. It did not take into account the economic savings in the private sector, nor the time lost from work by parents, from school for the child and the psychological and physical suffering. Similar results were found earlier in Louisiana and Texas. Just last month, a study in the UKusing extraction rates as a marker also found that it was much higher in the non fluoridated area.
Water fluoridation has been showed to be associated with a higher incidence of fluorosis. 41% of 12 year old kids in US has dental fluorosis. Yes, 41%! I was surprised when I first noticed the number. Since then, I pay more attention to the white spots on the teeth of my patients. I found that actually it is quite common to have those white spots once you pay attention. They are so tiny and not obvious that you would miss them easily. Fluorosis happens in Meadville even though there is no water fluoridation. There is fluoride in the tooth paste and in many commercial beverages such as tea and even soft drinks. However, I do not see it as a problem. I would say it is a plus. There are fewer cavities! Do you know anyone who lives in Erie, Pittsburgh? Ask them if they have heard about fluorosis from their dentists? Do their kids have fluorosis? Most would not even know that there was any controversy.
Occasionally you may hear that the source of fluoride for water fluoridation is from an industrial waste in the production of fertilizer. This is definitely not the case. The chemical used for water fluoridation is flurosilicic acid. Phosphate rock containing fluoride and silica are heated with sulfuric acid (H2SO4) releasing HF and SF4, which are captured by vacuum evaporators, then condensed to 23% flurosilicic acid (H2SiF4). Other than for the use for water fluoridation, it is also sold for the production of Aluminum Fluoride and other fluoride product. It is not an industrial waste. As in any rock, the phosphate rock may contain some heavy metal or arsenic. Some anti-fluoride activists use a scare tactic saying that flurosilicic acid is not FDA approved and the water would be contaminated by arsenic. In reality, it is the Environmental Protection Agency(EPA) that has the authority over the safety of community drinking water, as specified in the Safe Drinking Water Act. The EPA sets a maximum contaminant level (MCL) – the concentration allowed for various organism or substances. The EPA appoints a group of nonprofit nongovernmental organizations led by the National Sanitation Foundation (NSF) and American National Standards Institute (ANSI) to develop NSF/ANSI standard 60. The NSF certification programrequires annual, unannounced inspections of production and distribution facilities. On the other hand, for the API (active pharmaceutical ingredient) such as NaF (sodium fluoride), the FDA inspected about 40 % of the domestic facilities in a year and only 11% for foreign establishments. There is no legal requirement for FDA to inspect. It is up to the FDA personnel to decide which facilities to inspect. NaF is unlikely to have the same priority as the facilities that produce unstable substances, such as vaccines. Now, let us look at the inspection results. Is there any concern about arsenic? Please look at Figure 4. The max arsenic level for the sample was 0.6 ppb, 50% sample had a non-detectable level, while the MCL is 10 ppb and the NSF/ANSI 60 level is 1ppb. MCL is the level that EPA would accept if it occurs naturally, and NSF/ANSI 60 is the one that limit what you can add into the water. That means in the 4 years listed, there was not a single specimen not passing the inspection. Of course you may be concerned that all these tests were done by the organizations that have an association with the federal government. Are there any independent studies out there have the same finding? Yes! In 2003, in discussion about whether to stop water fluoridation, the residents of Fort Collins, CO formed the Fort Collins Fluoride Technical Study Group. In the report, they said that ‘there was no evidence that the addition of HFS increased the concentrations of copper, manganese, zinc, cadmium, nickel, or molybdenum. The concentrations of arsenic and lead were below the detection limit for the Fort Collins Water Quality Control Laboratory. The report was a very comprehensive one and contained many experts’ effort. It is worthy to read if you want to know more about water fluoridation.
Anyway, if you live in our area, and use well water, you may need to test your water. We are in an area with highest chance of underground water with high arsenic level.(Figure 5) In Conneaut Lake, the city water has a very high level of arsenic and with the new MCL of 10 ppb set in 2006, they have developed a method to remove it. Before removal, the level was 28 ppb, after removal, it was lowered to average 5 ppb, with an incidence of up to 21.4 ppb. I do not know the number in Meadville, but it would be less than 10 ppb set by the EPA. Anyway, you can see that the amount of arsenic possibly introduced into the water due to fluoridation is of a different order of magnitude compared with the nature.
In March, 2014, Public Health England published a very comprehensive report on water fluoridation. They used the data from the whole country – national hospital and clinic records, national cancer registry, national statistics, and national cytogenetic registry data to evaluate dental caries at different ages, dental fluorosis, bone health, renal effect, mortality, birth defect, and different forms of cancer. It is the latest data supporting that water fluoridation is safe and effective. It is very comprehensive, detailed, and convincing.
As a medical doctor, I can only say that water fluoridation is safe and effective. I cannot make the decision for others. This is why the federal government wants the local governments to make their decision. A very good comparison is the helmet law for motorcycles. Helmet has been shown to provide significant reductions in head and neck injuries in case of accidents. There is no doubt in the data. Yet the law allows people to have their choice. However, it is different in water fluoridation. Those making the decision not to have fluoride in the tap water are equal to taking away the choice from others who would benefit greatly. Moreover, helmets cause discomfort. It is a trade off for the rider. For water fluoridation, there is no trade off. The only problem is ignorance and fear. That is why I want to help with my professional knowledge. I have looked into nearly all the aspects – incidences of mechanical failure in the water plants, effect for patients with chronic kidney disease, infant formula issue, lead contamination, impact of health inequality, hip fractures, kidney stones, hypothyroidism, bladder cancer, other cancers, birth defects, osteosarcoma in pets and environmental effect etc. I have no ties to big industry or government. I am not an expert in epidemiology or statistics. I look at the data myself and independently. I may be wrong in some of the technical details. If anyone has any questions, please e-mail me at email@example.com and let us discuss in detail.
Raymond Leung, MD, FAAP