Part of the Fluoride Debate: http://openparachute.wordpress.com/fluoride-debate/#comment-48169
Between 40% to 70% of total exposure comes from water. The 50% number is easy for approximation. Obviously wide individual variations.
The increase in total exposure is one of my biggest concerns. Note the increase in dental fluorosis. And further, individual fluoridated water consumption is down, but dental fluorosis increases. Why? Other sources are providing more fluoride. And some of those other sources are rather important, such as toothpaste, pesticides, post-harvest fumigants, etc. But as long as many are ingesting too much fluoride from water, these other uses of fluoride must be more closely controlled to avoid excess exposure.
Ken, you further raised a very important point. “Philosophically probably everything we know is “wrong” to some extent. . . . As you say we usually don’t know what we a wrong about – however, we can develop levels of confidence sufficient to use what we know. And it is really naive to suggest we do nothing just in case we might be wrong.”
I fully agree with your balanced public health reasoned philosophy. And when we find something is “wrong” to some extent for some high risk individuals, would it not be best to at least put a notice on the package of caution?
I agree, everything has risk and we should not sit by and do nothing in the face of highly contagious lethal diseases. Dental caries is not highly contagious or lethal.
What happens when public health officials have their reputations on the line and have to promote something which later is seen to be wrong? The theory becomes locked in concrete. Note the Tuskegee experiment. 30 years before it was stopped, treatments were known, yet the US Public Health Services and CDC continued the barbaric experiment for decades, leaving men, women and children to become infected and sick and die. Oh, yes, for the greater good some are sacrificed. The experiment was started just before fluoridation.
Total exposure and the variation of fluoride ingestion from all sources is the main reason I am pushing hard for studies, like those mostly done in China, India and other countries, where serum and urine fluoride are measured. Estimates based on assumptions is not good scientific measurements. We need and can measure individual serum fluoride.
The main issues which changed my mind on fluoridation were:
A. Total exposure is increasing. More and more fluoride is being used in other places increasing total exposure. Who reviews total exposure from all sources and starts to reduce excess exposure? No one. Governments are fragmented with no one looking at the big picture. The suggestion of possibly lowering concentration of fluoride in water to 0.7 ppm, is in part recognition that total exposure is constantly increasing. Most logical to reduce fluoride in water because other sources of fluoride have additional benefits, such as toothpaste, pesticides, medications, post-harvest fumigants, lubricants, teflon, freon, clothes, Scotchguard, etc. etc. When fluoridation started, no increase in dental fluorosis was expected. Then they said 10% increase. Then they said 20% increase. Now we have 41% of children with dental fluorosis. Do we want 100% to have dental fluorosis?
B. Benefit of fluoridation. Without one single prospective RCT, which could be done, we are left with lower quality studies. I wish I could post graphs here so you could see the trends. Countries with our without fluoridated water or/and fluoridated salt all have similar low levels of dental caries. Same for states and counties. No common cause variation with fluoridation. No public health benefit can be seen.
However, I personally was 100% convinced I could see the benefit of fluoride in my patients. Teeth look harder, shinier. So it was a struggle to accept and understand that fluoridation of water no longer provided dental health benefit, certainly little or no life time dental health benefit. Some lowering of caries if confounding problems are ignored. Not a lowering of dental expenses, not fewer dentists in fluoridated communities, no evidence at the community wide level of benefit. Forgot who said, “the success of a public health measure must be measured in the community at large.”
C. Harm from excess fluoride ingestion. There is not dispute, too much fluoride increases health risks.
D. Ethics. Is giving everyone fluoride, even when they are highly chemically sensitive to fluoride or ingesting too much from other sources, when other options are available, ethically reasonable?
For me, brains are more important than teeth. I can fix teeth, no one can fix IQ.