The authors carried out a study on the intellectual abilities and fluoride/iodine metabolism of children living in a high fluoride-high iodine area. Among the results: the percentage of the general population living in this fluoride/iodine-contaminated region that suffered from goiter (clinical thyroid enlargement) was 3.8%, the rate of children already showing some thyroid enlargement was 29.80%. Similarly, the rate of dental fluorosis for the general population was 35.48%, while for children it was 72.98%. Student subjects had average IQs of 76.67±7.75, with 16.67% of the IQs in the “low” category. The iodine content and fluoride content of the children’s urine were 816.25±1.80 ?g/L and 2.08±1.08 mg/L, respectively, significantly higher than the control. The thyroid glands of the subjects showed a markedly lower uptake rate of iodine-131 when compared with the control, the values after 3 hr and 24 hr were 9.36±1.55% and 9.26±4.63%, respectively, and the blood serum levels of thyroid stimulating hormone (TSH) were significantly higher than the control. The results indicate that high levels of fluoride and iodine have a serious damaging effect on the body, and should be given greater attention.
Translated by Julian Brooke for Fluoride Action Network and published with the permission of the Chinese Journal of Endemiology 1994 October;15(4):296-8 in the journal Fluoride.