[Zhang Fei]

The children in high fluoride areas had significantly lower IQ than those who lived in low fluoride areas,” write Choi et al

I'd like to see the racial composition of the two areas. My guess is that the high fluoride areas included the big cities (lot of blacks and Hispanics, whose average IQ is in the 80 range), while the low fluoride areas were rural or suburban areas with mainly white residents (average IQ ~ 100).

[Black Agnes]

Actually one of the bigger recent studies that showed IQ decrease with increasing fluoride levels was done in China using Han Chinese.