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Comparative Assessment of the Physical and Mental Development of Children in an Endemic Fluorosis Area with and without Water Improvement Programs.
| Chinese Journal of Control of Endemic Diseases | Originally published in Chinese; translation by the Fluoride Action Network | Yao L, Deng Y, Yang S, Zhou J, Wang X, Cui Z. | 9(4);230.
China-IQ Endemic fluorosis areas Brain Cellular/Tissue Effects Cognitive Function Dental Fluorosis IQ Score Human Study
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Abstract

Tests were performed to compare the IQ and physical development of 7-­to-­14-­year-old children from endemic fluorosis areas, with and without water improvement programs, with children from a non-fluorosis area. The results showed that the average IQ of children in each age group from the fluorosis area without water improvement is lower than those from either the fluorosis area with water improvement or the non-fluorosis area (P<0.01). When comparing 7-­to-­8-­year-­old children born after the implementation of the water improvement program to children of the same age group in the non-fluorosis area, no obvious difference was found. Comparisons of the height, weight, and sitting height of children in the fluorosis area without water improvement and the fluorosis area with  water improvement revealed an obvious difference for the 12-­to-­14-­year-­old age group. No obvious differences were found between the fluorosis area with water improvement and the non-­fluorosis area. These results show that water improvement and defluoridation can improve the mental and physical development of children in development of children in a fluorosis area.

Keywords: Endemic fluorosis, IQ, Physical Development, Children

EXCERPTS:

2.Results and Analysis

2.1 Intelligence Tests

Intelligence tests of the 326 children aged 7­-to-12-­years-­old in the fluorosis area with water improvement showed the average IQ to be 97.83±11.27. The 183 children from the fluorosis area without water improvement had an average IQ of 94.89±11.15 and the 314 children from the non-­fluorosis area had an average IQ of 99.98 ±12.21. The IQ of the fluorosis area without water improvement was obviously lower than both the fluorosis area with water improvement and the non-­fluorosis area (t=2.85, 4.67; P<0.01), and the IQ of the  non-fluorosis area was higher than the fluorosis area with water improvement (t=2.31, P<0.05). As to the average IQ of each particular age group, the fluorosis area without water water improvement was lower than both the fluorosis area with water improvement and the non-fluorosis area (P<0.01). The differences in IQ between the 7-8-year-old children in the fluorosis area with water improvement and the non-fluorois area were not obvious (t=0.09, P>0.05). Among the 9-­to-12-­year-old children, however, the average IQ in the fluorosis area with water improvement was lower than the non-fluorosis area (P<0.01), see table 1.2.2.

3. Discussion

Since the absorption rate of fluoride among children is higher than adults, the effects and harm of high fluoride on the growth and development of  children cannot be neglected. As reported in previous research, the weight of the brain among 6-year-old children is about 1,200g, which is 90% of the respective weight in adults [3]. Therefore, the pre-6-year-old period is a critical one for children’s mental development. Drinking water with high fluoride content during this time thus has a significant impact on the intelligence development of children. In this survey, the IQ of two groups of children, who were 7 or 8 years old and were born after drinking low fluoride water, was not obviously different from the IQ of children from the non-fluorosis area. This is mainly because the children  of this age group have always been  drinking low fluoride water and have not been exposed to high fluoride. By contrast, since the water improvement program was implemented 8 years ago, the children who are currently 9-­to-­12-­years-­old were exposed to a high fluoride environment either in the fetal period in the womb or within the four years after birth. Although they are now drinking low fluoride water, they have been exposed to various levels of fluoride harm during the critical period of childhood brain development and their mental development has been influenced to a certain degree. As a result, their current IQ is still lower than that of the non­-fluorosis area. The results of measurements of morphological indices showed that the height, weight and sitting height of children in the fluorosis area without water improvement were lower than the groups from the fluorosis area with water improvement and the the non-fluorosis area. The age group that had obvious differences was mainly the 12-­to-­14-year-­olds, which indicates that this age group is at the second rapid growth period for children’s growth and  development. High fluoride delays and postpones the growth and development of children. Comparing the chest circumference among the three groups, there was no obvious difference, which indicates that high fluoride exposure had little effect on the development of chest circumference.

References

[1] YUBIN TAN. THE EFFECTS OF FLUORIDE ON THE METABOLISM AND EACH OF THE SYSTEM IN THE BODY, Chinese Journal of Control of Endemic Diseases, 1994; 9(4);230