The study, published in PNAS, examined Wisconsin state testing records, archival information about when Wisconsin cities began to fluoridate their water, and data from the Wisconsin Longitudinal Study, which has followed a random sample of 10,317 high school seniors from 1957 through 2026. Key findings include:
- There is no evidence supporting a connection between community water fluoridation and children’s IQ.
- There is also no evidence supporting a connection between community water fluoridation and cognitive functioning at various points later in life.
- Findings confirm evidence published in previous research which also used a national sample, but considered school achievement test scores instead of actual IQ scores.
But shouldn’t it? That’s what is claimed. But I’m certain enough there’s a large enough populace that doesn’t drink tap water to confound results.
copying my answer about fluoride, again:
Fluoride in the water is the opposite of bad, it’s good for your teeth. It’s in toothpaste for a reason! There is no reasonable evidence that fluoride causes any major health problems, in fact, the fluoridation of water is dubbed as one of the largest public health accomplishments in a while. In addition, the fluoride added to water is miniscule, tiny, far far too low in concentration to be toxic. It also occurs in plenty of foods naturally too (fruits, seafood, spinach, etc.)
Some more information of fluoride:
https://my.clevelandclinic.org/health/treatments/11195-fluoride
https://www.cdc.gov/oral-health/prevention/about-fluoride.html
https://www.sciencedirect.com/science/article/abs/pii/S000291652334718X
According to Wikipedia (I know, not the most accurate source. I just needed a quick statistic) the U.S. has a fluoride level of 0.7 mg / L since 2015. Poking around for other countries, it looks like 0.7-1.2 mg / L is the range that most countries add to their water supply.
For reference, the WHO recommends 1.5 mg / L as the upper limit. Additionally, in many places, the groundwater has fluoride levels a bit higher than that.
Ok?
Seems about 20 people, including you, didn’t get it.
So here’s what I was thinking earlier:
If you feed a pig sweets. What happens?
Their teeth rot. Same for humans.
If an animals teeth are rotting, oh boy. Guess what? I mean science will greet you with many associations (I’m sure some are causal)… Including heart disease, cognitive impairments, chronic inflammation, infection, carries, abcesses, etc.
Long story short, you really don’t want to eat that animal. And I imagine you really don’t want to be that animal.
Really short: shit breath often leads to a shit head.
So… if fluoride is so great… Apparently. So why doesn’t this show up, if it’s so great?
I would expect a positive association, based on the hype. This says it found none.
So what’s the benefit then?
Bad oral hygiene is associated with IQ decline. So if fluoride is helping alleviate that, where’s that data?
Protection against tooth decay? I’m not sure I understand your point. That is a pretty big health benefit, I think, not sure why you think it’s not a positive effect. There are plenty of studies as to how fluoride (in the water or as toothpaste) can protect against cavities.
I will reiterate my point that fluoride levels in water is too low to be dangerous, as the WHO recommends a maximum of 1.5 mg / L for fluoridation of water, while most countries that implement it use a concentration of 0.7-1.2 mg / L. Additionally, fluoride is also naturally present in many fruits, seafood, etc. as well as many groundwater sources that are perfectly safe to consume.
edit: I think I understand what you are talking about. Yes, fluoride does not increase nor decrease IQ levels. Its main job is to protect against tooth decay. But that is still a public health benefit, no?
I guess I’ll reiterate. Many studies from early studies, after fluoridation became more common versus before, have found numerous benefits. Across the globe…
I think this study is more absence of evidence rather than evidence of absence.
Like… Shit. Say a kid has a cavity do you think he’s going to be focusing on his homework or his tooth hurting?
Decreasing number of cavities in children != increasing IQ
IQ only measures the ability to solve problems and pattern-match. And I would assume IQ tests are taken after cavities are dealt with.
To give an example, it’s the same thing as if you tried to give an IQ test to someone who, in the past, has had a bacterial infection. Then, when the person is perfectly healthy, you give them an IQ test once, then some antibiotics, then another IQ test giving the same result as the first. You would not conclude that antibiotics are ineffective and should be banned!
Fluoride doesn’t impact your IQ.
Whatever you’re on … does.
That is all.
Other studies disagree with that conclusion.
I mean… I can take any IQ test against you and I can tell you what I’m going to get… 98th percentile. That’s 130-140. Not perfect. But certainly above average.
Will you even break a hundred?
☝️🤓
Huh? It’s there for cavity prevention.
Read any scientific literature?
Yes, regularly.
Removed by mod
Are you having a stroke?
I’ll accept the null answer.
🍞🔥
Wooosh
The usefulness of fluoride is pretty well established at this point. If you have new data, please share it.
This study disagrees with you.
No significant difference.
You might wanna double check those p-values.
The study suggests no change in IQ values, not no change when it comes to protecting your teeth. To copy an example from a previous comment:
IQ only measures the ability to solve problems and pattern-match. And I would assume IQ tests are taken after cavities are dealt with. It’s the same thing as if you tried to give an IQ test to someone who, in the past, has had a bacterial infection. Then, when the person is perfectly healthy, you give them an IQ test once, then some antibiotics, then another IQ test giving the same result as the first. You would not conclude that antibiotics are ineffective and should be banned!
Wtf?
frongt noted that the fluoride is beneficial (for preventing tooth decay), while you state that the study denies this. This is untrue, as it just shows that fluoride doesn’t affect IQ (which primarily focuses on measuring logical thinking). It does not look at how it protects against cavities, there are plenty of studies on that already!
Your argument would replace bacterial infection with cavities and antibiotics with fluoridised water. Like the example with antibiotics, it is not a reasonable conclusion to state that no change to IQ = fluoridation in water is ineffective.