Fluoridation in the UK

[Ivor the Engineer]

Of course, those individuals with a disposition towards conspiracy theories might think "they" are adding folic acid to bread to mask the increase in Down's syndrome caused by adding fluoride to tap water.

 

[Silly Green Monkey]

Look up Colorado Brown Spot Disease. That's where people got the idea that fluoride could protect teeth, because natural high levels in the water were. Incidentally, some regions have fluoride levels that are naturally too high, and must be filtered, should that water be left alone in terms of fluoride as well?

 

[Ivor the Engineer]

The bottom line is there is no good quality evidence to support putting fluoride in tap water.

 

[plumjam]

Look up Colorado Brown Spot Disease. That's where people got the idea that fluoride could protect teeth, because natural high levels in the water were. Incidentally, some regions have fluoride levels that are naturally too high, and must be filtered, should that water be left alone in terms of fluoride as well?

The water I mean should be left alone is the water currently produced by the water companies here in the UK (at least in my region). I'm not talking about drinking directly from streams and springs.

 

[lionking]

Well unless you ignore what JJM posted. So please explain again why our government is doing this to us? maybe this thread should be moved to the CT sub forum.

 

[Ivor the Engineer]

Look up Colorado Brown Spot Disease. That's where people got the idea that fluoride could protect teeth, because natural high levels in the water were.

Yeah, not much has changed in dental hygiene since the start of the 20th century*.

Incidentally, some regions have fluoride levels that are naturally too high, and must be filtered, should that water be left alone in terms of fluoride as well?

Don't be daft. No one has used the 'natural so it's good' argument (yet).

*Though more NHS dentists in the UK going private because they can make more money while doing less work might lead to dental health declining amongst those who cannot afford to pay.

 

[Ocelot]

The bottom line is there is no good quality evidence to support putting fluoride in tap water.

What sort of evidence would be good enough?

 

[fls]

The bottom line is there is no good quality evidence to support putting fluoride in tap water.

There is no good quality evidence that putting folic acid in flour prevents birth defects, that putting iodine in salt prevents thyroid disease, that smoking cigarettes or exposure to asbestos causes lung cancer, that DDT interferes with the reproduction of birds, that Thalidomide causes birth defects, or that radiation causes cancer.

There is, however, Grade B evidence for all of the above which counts as 'fair'. Make of it what you will.

Linda

 

[plumjam]

Personally I think we should, as a society, add incense fumes to the air. This would have a general soothing effect on the population, would reduce violent crime, and mask all but the worst cases of B.O. and hallitosis; as well as many industrial odours.

(It would also provide a net saving on policing, probation, counselling, conflict resolution, casualty services, and reduce insurance premiums.)

 

[Ivor the Engineer]

There is no good quality evidence that putting folic acid in flour prevents birth defects, that putting iodine in salt prevents thyroid disease, that smoking cigarettes or exposure to asbestos causes lung cancer, that DDT interferes with the reproduction of birds, that Thalidomide causes birth defects, or that radiation causes cancer.

There is, however, Grade B evidence for all of the above which counts as 'fair'. Make of it what you will.

Linda

What does that have to do with putting fluoride in tap water?

It should be easy to find out if it is worth while. Many countries (including the UK) do not have universal fluoridation of tap water. If it does make a practically significant difference to dental (or other aspects of) health it is easy to find large groups of people who have similar lifestyles other than regular consumption of fluoridated tap water over decades.

That conclusive research has not been published speaks volumes about the likely size of the effect.

 

[fls]

What does that have to do with putting fluoride in tap water?

You are the one that brought up 'good' evidence. If evidence only of a particular type (randomized controlled trials) is relevant, then why did anyone think it was reasonable to act on those other issues, given that the evidence (at best) matches that for fluoridation?

It should be easy to find out if it is worth while. Many countries (including the UK) do not have universal fluoridation of tap water. If it does make a practically significant difference to dental (or other aspects of) health it is easy to find large groups of people who have similar lifestyles other than regular consumption of fluoridated tap water over decades.

Yes, it is. You've already dismissed it as not 'good' evidence, though.

That conclusive research has not been published speaks volumes about the likely size of the effect.

That conclusive research has not been performed doesn't say much of anything about the likely size of the effect.

Linda

 

[Ivor the Engineer]

You are the one that brought up 'good' evidence. If evidence only of a particular type (randomized controlled trials) is relevant, then why did anyone think it was reasonable to act on those other issues, given that the evidence (at best) matches that for fluoridation?

Because most of the conditions on the list in your previous post are associated with significant disability or premature death. Reducing the number of fillings people have isn't really in the same category.

Yes, it is. You've already dismissed it as not 'good' evidence, though.

I have done no such thing. The authors of the report I quoted said:

We were unable to discover any reliable good-quality evidence in the fluoridation literature world-wide.

What evidence we found suggested that water fluoridation was likely to have a beneficial effect, but that the range could be anywhere from a substantial benefit to a slight disbenefit to children's teeth.

How can such a wide margin of error still exist given the number of years fluoridation of water has been implemented?

That conclusive research has not been performed doesn't say much of anything about the likely size of the effect.

Linda

It does when what is effectively a massive experiment has been running for decades and the data can't rule out the harm or the null hypotheses.

 

[fls]

Because most of the conditions on the list in your previous post are associated with significant disability or premature death. Reducing the number of fillings people have isn't really in the same category.

If your argument is that the problem is trivial, then why bring up the issue of evidence in the first place?

I have done no such thing.

Then what did you mean when you said, "the bottom line is there is no good quality evidence to support putting fluoride in tap water"?

How can such a wide margin of error still exist given the number of years fluoridation of water has been implemented?

It does when what is effectively a massive experiment has been running for decades and the data can't rule out the harm or the null hypotheses.

I just thought you might like to know that the same thing applies to much of what we do. I'm happy to go along with what everyone else wants, all I ask is that a consistent threshold is established. I say this because I've been buying up Thalidomide stock while it's still cheap.

Linda

 

[Ivor the Engineer]

If your argument is that the problem is trivial, then why bring up the issue of evidence in the first place?

I don't know about you, but my tolerance to the risks of treatment increases the more significant the risks of non-treatment are.

I also don't know what the situation is in the US or Canada regarding access to expert dental care and advice, but (in theory at least) anyone in the UK can access it regularly for minimal cost. That they choose to ignore their dentist's recommendations is their own choice.

Then what did you mean when you said, "the bottom line is there is no good quality evidence to support putting fluoride in tap water"?

I meant people who have (presumably) more expertise in this area that I have attempted to find good quality evidence and drawn a blank.

I just thought you might like to know that the same thing applies to much of what we do. I'm happy to go along with what everyone else wants, all I ask is that a consistent threshold is established. I say this because I've been buying up Thalidomide stock while it's still cheap.

Linda

I think the threshold should be set depending on the risks of treatment and non-treatment. Is that what you mean when you ask for 'a consistent threshold to be established'?

 

[fls]

I meant people who have (presumably) more expertise in this area that I have attempted to find good quality evidence and drawn a blank.

Which means that this suggestion...

"It should be easy to find out if it is worth while. Many countries (including the UK) do not have universal fluoridation of tap water. If it does make a practically significant difference to dental (or other aspects of) health it is easy to find large groups of people who have similar lifestyles other than regular consumption of fluoridated tap water over decades."

...would be similarly discarded, is all.

I think the threshold should be set depending on the risks of treatment and non-treatment. Is that what you mean when you ask for 'a consistent threshold to be established'?

I'd just like it not to be wildly different from one topic to the next - flimsy anecdotes are sufficient in one case, while in another, only the most highly unethical research will do (not necessarily referring to anything you've said).

Linda

 

[Ivor the Engineer]

Which means that this suggestion...

"It should be easy to find out if it is worth while. Many countries (including the UK) do not have universal fluoridation of tap water. If it does make a practically significant difference to dental (or other aspects of) health it is easy to find large groups of people who have similar lifestyles other than regular consumption of fluoridated tap water over decades."

...would be similarly discarded, is all.

Really? A well planned and executed prospective cohort study could not be considered good quality evidence?

 

[dogjones]

Have some Ben Goldacre on the subject.

http://www.badscience.net/2008/02/foreign-substances-in-your-precious-bodily-fluids/

 

[fls]

Really? A well planned and executed prospective cohort study could not be considered good quality evidence?

The reason the studies were rated as not good quality was because they were not blinded randomized controlled trials.

Linda

 

[ectoplasm]

Of course, by the same measure, we don't really know that smoking causes lung cancer. Damn government interference!

However, we should leave well enough alone. The Brits are known for having excellent teeth, after all.

Linda

Q: Whats red and white with long yellow teeth?

A: A Brit on a beach holiday.

 

[Ivor the Engineer]

The reason the studies were rated as not good quality was because they were not blinded randomized controlled trials.

Linda

I understood from the report that good-quality (at least as far as the authors of the report were concerned) could be achieved by a non-randomised design, so long as the study was of sufficient duration and those assessing outcomes were blinded to the status of the participants.

http://www.york.ac.uk/inst/crd/pdf/fluorid.pdf

The following methodological issues were considered when assessing studies for inclusion: selection, confounding, and measurement. Study designs are often graded hierarchically according to their quality, or degree to which they are susceptible to bias. The hierarchy indicates which studies should be given most weight in a synthesis. In this review, the degree to which each study dealt with the methodological issues was graded into three levels of evidence:

LEVEL A (HIGHEST QUALITY OF EVIDENCE, MINIMAL RISK OF BIAS)
• Prospective studies that started within one year of either initiation or discontinuation of water fluoridation and have a follow up of at least two years for positive effects and at least five years for negative effects.
• Studies either randomised or address at least three possible confounding factors and adjust for these in the analysis where appropriate.
• Studies where fluoridation status of participants is unknown to those assessing outcomes.

...

Studies meeting two of the three criteria for a given evidence level were assigned the next level down. For example, if a study met the criteria for prospective design and blinding for level A, but was neither randomised nor controlled for three or more potential confounding factors, it was assigned level B. Evidence rated below level B was not considered in our assessment of positive effects. However, this restricted assessment of the evidence for Objective 3, so the best level of evidence relevant to this objective (from any study design) was included. In our assessment of possible negative effects, all levels of evidence were considered. Adjustment for confounding factors required analysis of data, simply stating that two study groups were similar on noted confounding factors was not considered adequate.

Overall the NNT and NNH (fluorosis) were much the same (~6), though the quality of the evidence for fluorosis was much lower than that for the prevention of tooth decay.