Abstract

Wechsler Intelligence Test IQ scores of 160 children, 8–14 years old, from nine schools in an area of high fluoride and low iodine averaged 64.8 compared with 85.0 (p<0.01) for 169 children of the same ages from seven schools in an area with low iodine only. Among the first group 65 (40.6%) had IQs below 60, but only 23 (13.6%) among the second group had scores this low. In each group the IQs of the boys and girls did not differ significantly. Clearly,  exposure to the combination of high fluoride and low iodine was more deleterious than to low iodine alone.