[colordrops]

You should re-read the study I linked:

"The average loss in IQ was reported as a standardized weighted mean difference of 0.45, which would be approximately equivalent to seven IQ points for commonly used IQ scores with a standard deviation of 15."

Seven points IQ difference.

Also, if you bother to look at the data in the linked paper, many of the regions with measurable deficits were in the 0.5 to 2 mg/L range, well within typical treatment levels in the US.

[defrost]

Fair point re: IQ - I misread that.

> Also, if you bother to look at the data in the linked paper, ...

Excuse me? Mind the shade please.

> many of the regions with measurable deficits were in the 0.5 to 2 mg/L range

Exactly how many of the 27 studies listed actually had "high" fluoride values in that range?

If you bother to look at the data you might concede it's not "many" by a long shot.

More to the point, in those few studies with low fluoride levels how much was IQ correlated to fall?

The meta study findings were:

    Findings from our meta-analyses of 27 studies published over 22 years suggest an inverse association between high fluoride exposure and children’s intelligence. Children who lived in areas with high fluoride exposure had lower IQ scores than those who lived in low-exposure or control areas.

Note Well: "than those who lived in low-exposure or control areas."

It's a meta study.

It looked at studies with low levels of fluoride AND at studies with high levels of fluoride.

It determined that high levels of fluorine are not good (and that many of the studies had other issues such as lead, arsenic, iodine that had to be dealt with).