[jarin]

It should be noted that the negative effects were found in areas with much higher levels of fluoridation (i.e. areas of China with naturally occurring fluoride in groundwater) than are typical in the US. There wasn't enough information to draw conclusions about US fluoridation levels.

[colordrops]

The limit for fluoride in US drinking water is 4.0 mg/L, and there are regions in the paper that report cognitive impairment that are much lower than this. You should consider posting analysis or sources for your statements, or just not comment and let the paper speak for itself.