effect of high water fluoride concentration on the intellectual development of children in makoo/iran.

prolonged excessive intake of fluoride during child's growth and development stages has been associated with mental and physical problems. the aim of this study was to investigate the effect of excessive fluoride intake on the intelligence quotient (iq) of children living in five rural areas in makoo/iran.in this cross-sectional study, 293 children aged 6-11 years were selected from five villages in makoo with normal fluoride (0.8±0.3 ppm), medium fluoride (3.1±0.9 ppm) and high fluoride (5.2±1.1 ppm) in their water supplies. the iq of each child was measured by the raven's test. educational and residential information and the medical history of each child was recorded by a questionnaire completed by the parents. data were analyzed by anova test with a significance level of 0.05.the mean iq scores decreased from 97.77±18.91 for the normal fluoride group to 89.03±12.99 for the medium fluoride group and to 88.58±16.01 for the high fluoride group (p=0.001).children residing in areas with higher than normal water fluoride levels demonstrated more impaired development of intelligence. thus, children's intelligence may be affected by high water fluoride levels.