> fluoride intake levels (0.93 [0.43] vs 0.30 [0.26] mg of fluoride per day; P = .001).
> Children had mean (SD) Full Scale IQ scores of 107.16 (13.26), range 52-143, with girls showing significantly higher mean (SD) scores than boys: 109.56 (11.96) vs 104.61 (14.09); P = .001.
The average IQ of people in the UK is 99.12 and in Canada 99.52 [3]. Let us suppose that the hypothesis is true; it is expected then that in a country with higher average consumption of fluoride, we would, consistently, see lower average IQ.
> Above-average consumption of tea, as recorded in Great Britain, could result in fluoride intakes as high as 8.9 mg per day [4];
We observe that the average consumption of Fluoride is about an order of magnitude larger in the UK, yet, IQs are almost identical. Which hints that if such a relationship exists, it is not as pronounced (5 IQ points) as the article claims.
Maybe somehow women in the UK consume 20x less Fluoride when they are pregnant (what's the prob of this?), maybe people in the UK are just built different and their superior genes compensate and without the Fluoride they'd be at 104-105ish. Given history and similarity between societies, this looks unlikely.
So until a causal mechanism is found, I am inclined to disagree over the "proven fact" statement.
> We observe that the average consumption of Fluoride is about an order of magnitude larger in the UK, yet, IQs are almost identical. Which hints that if such a relationship exists, it is not as pronounced (5 IQ points) as the article claims.
Ecological comparisons are towards the bottom of the evidence hierarchy because there are any number of cofounders at play.
For example you could accidentally conclude that smoking is healthy because smoking tracks with affluence in poorer countries.
So I would reject the notion that we should or shouldn’t see IQ differences in very different populations which is why you want to do controlled research on different cohorts in the same population.
Finally, a causal mechanism is only a cherry on top but it’s not necessary for strong causal inference. Our mechanistic explanations are repeatedly wrong and/or inexhaustive. Fortunately, we can perform good quality studies instead like mendelian randomization.
At this point I think fluoride falls firmly into the category of "needs more research", but if you're pregnant it seems like actively trying to reduce your intake of fluoride is a sensible precaution since that's unlikely to have any negative effect on you or the kid, but if fluoride does cause problems you could dodge a bullet before the science catches up.
Your bar for "proven facts" is very low - you might want to reconsider what you read as truth and put a bit more of a filter on. I say this for your own benefit - as nothing you do bears on my life.
Life on earth is a highly interconnected system, otherwise, what's the point of educating people on issues like pollution, climate change, alcohol, etc.?
It is connected however my advice for this individual has no direct bearing on my life and am merely hoping for their own benefit they are more discerning about their ability to comprehend information. Yes you can argue that a society that is more discerning has an impact - though that's a bit too hand wavy.
Right, I could say some nonsense about how your politically polarised mindset blinds you to obvious facts. It'll be very persuasive I'm sure. Instead I'll believe a bunch of dentists who have no expertise in neuroscience to put aside their egos and come to a consensus. Just a couple more decades no worries. It's like some Idiocracy thing where some group convinces a population to put a neurotoxin into the water supply. Art imitates life I guess, the movie did come out later than this.
I want to understand dose-dependency on the relationship between fluoride and IQ. Why do we have to put fluoride in the drinking water to "protect kids' teeth"? Wouldn't it be better to simply provide toothpaste and toothbrushes for free to school-age children?
Because putting fluoride in water leads to demonstrably better outcomes than just expecting parents to get kids to brush their teeth. Fluoride has no empirical impact on anything other than positive health outcomes. It would be dumb not to use it. If you are worried about what's in your water a reverse osmosis system will remove things much more harmful than fluoride and you can get rid of your horrible fluoride while you're at it.
I don't understand your holier-than-thou tone about fluoride. Sadly, the fluoride stuff is still up for discussion. Why is it a "taboo" to discuss this? https://www.nature.com/articles/s41390-020-0973-8
That isn't what the article says. It isn't even evaluation of other people's research, let alone novel research in itself. It's a "perspective" article commenting on human behavior.
Meanwhile researchers who have conducted proper meta-analyses of the literature have come to a negative conclusion on this topic:
In conclusion, based on the totality of currently available scientific evidence, the present review does not support the presumption that fluoride should be assessed as a human developmental neurotoxicant at the current exposure levels in Europe.
There have been a lot of studies done, dose-response studies too. It gets ignored in the US because of left-right polarization. Here are a few below. Believe what you want I guess but this is basically overwhelming evidence to me.
Thanks, and you can believe what you want as well.
That said, let's note please that these are all associational, rather than cause-and-effect findings. The matter should definitely be explored further - but in my book I would need significant evidence of a causative relationship to check the "overwhelming evidence" box.
https://www.nature.com/articles/s41390-020-0973-8