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.



I’ve survived over half a century without a water filter? For half of that, I was on a well.
Water filters are good when they filter out something you know is in the water that shouldn’t be.
Proud Flint resident right here ^
They’re also good when they filter out something you don’t know is in the water but shouldn’t be. You ever get that well water tested? Did that test include PFAS?
I saw a test that found Zero filters increased microplastics 10x or something like that.
Also, they’re pretty useless when they filter out beneficial minerals but miss the thing you didn’t know about that’ll kill you.
That well water got tested on a regular basis. It didn’t include PFAS because nobody tested for PFAS back then.
However, most filters today don’t filter PFAS. A good reverse osmosis filter will, or distillation. Problem with distillation is that it filters out all the good stuff too, so then you have to fortify your water.
Got it, I edited my comment