Fluoride Action Network



Objective: To explore the effect of endemic fluorosis caused by coal burning on the level of intelligence in children.

The Method: We randomly selected 20 school children from 4 areas between the ages of 8[1]12, whose characteristics fit the scope of our research. They were chosen from slight, moderate, and severe endemic fluorosis areas that were affected by regional fluoride poisoning brought on by the burning of coal, and a controlled, non[1]endemic area. We have used the used the CRT[1]RC to perform a test of the children’s intelligence levels, and we have examined the condition of their dental fluorosis. Urine samples were collected in the morning, and the fluoride content in the samples was measured by the fluoride ion selective electrode method.

The Results: We have found that those more severely impacted by dental fluorosis had a higher level of fluoride in their urine samples (P<0.01). A significant difference in the children’s levels of IQ could be observed amongst the different disease areas. The children’s level of IQ tended to decrease as the severity of dental fluorosis increased. There was a negative correlation between the children’s IQ level and urinary fluoride content (P<0.01). Significant differences could be seen in the abilities of comparative inference, serial relationship, and abstract inference between the different groups tested (P<0.05). In terms of cognition and analogical comparison abilities, the difference was not significant among the children from the different disease groups (P>0.05).

Conclusion: High exposure to fluoride most definitely has an adverse effect on the development of intelligence in children, in particular on the capability of abstract inference.