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January 7, 2011
(CNN) -- The federal government is recommending changing the amount of fluoride in drinking water for the first time in 50 years.
The Department of Health and Human Services and Environmental Protection Agency are proposing the change because of an increase in fluorosis -- a condition that causes spotting and streaking on children's teeth.
The government is proposing that the recommended amount of fluoride in drinking water be set at 0.7 milligrams per liter of water. The recommended range has been 0.7 to 1.2 milligrams per liter since 1962. The EPA will determine whether the maximum amount of fluoride allowed in water will also be lowered.
Dental fluorosis is a developmental disturbance of dental enamel caused by excessive exposure to high concentrations of fluoride during tooth development. The risk of fluoride overexposure occurs between the ages of 3 months and 8 years. In its mild forms (which are its most common), fluorosis often appears as unnoticeable, tiny white streaks or specks in the enamel of the tooth. In its most severe form, tooth appearance is marred by discoloration or brown markings. The enamel may be pitted, rough and hard to clean.  The spots and stains left by fluorosis are permanent and may darken over time.
Risks factors for dental fluorisis
Environ Health Perspect. 2007 April; 115(4): 643–647.
Published online 2007 January 9. doi: 10.1289/ehp.9270
Recently, in a cross-sectional study of 201 children in Araihazar, Bangladesh, exposure to arsenic (As) in drinking water has been shown to lower the scores on tests that measure children’s intellectual function before and after adjustment for sociodemographic features.
We investigated the effects of As and fluoride exposure on children’s intelligence and growth.
We report the results of a study of 720 children between 8 and 12 years of age in rural villages in Shanyin county, Shanxi province, China. The children were exposed to As at concentrations of 142 ± 106 μg/L (medium-As group) and 190 ± 183 μg/L (high-As group) in drinking water compared with the control group that was exposed to low concentrations of As (2 ± 3 μg/L) and low concentrations of fluoride (0.5 ± 0.2 mg/L). A study group of children exposed to high concentrations of fluoride (8.3 ± 1.9 mg/L) but low concentrations of As (3 ± 3 μg/L) was also included because of the common occurrence of elevated concentrations of fluoride in groundwater in our study area. A standardized IQ (intelligence quotient) test was modified for children in rural China and was based on the classic Raven’s test used to determine the effects of these exposures on children’s intelligence. A standardized measurement procedure for weight, height, chest circumference, and lung capacity was used to determine the effects of these exposures on children’s growth.
The mean IQ scores decreased from 105 ± 15 for the control group, to 101 ± 16 for the medium-As group (p < 0.05), and to 95 ± 17 for the high-As group (p < 0.01). The mean IQ score for the high-fluoride group was 101 ± 16 and significantly different from that of the control group (p < 0.05). Children in the control group were taller than those in the high-fluoride group (p < 0.05); weighed more than the those in the high-As group (p < 0.05); and had higher lung capacity than those in the medium-As group (p < 0.05).
Children’s intelligence and growth can be affected by high concentrations of As or fluoride. The IQ scores of the children in the high-As group were the lowest among the four groups we investigated. It is more significant that high concentrations of As affect children’s intelligence. It indicates that arsenic exposure can affect children’s intelligence and growth.
Effect of fluoride exposure on intelligence in children
Li, XS | Zhi, JL | Gao, RO
Fluoride. Vol. 28, no. 4, pp. 189-192. 1994.
The intelligence was measured of 907 children aged 8-13 years living in areas which differed in the amount of fluoride present in the environment. The Intelligence Quotient (IQ) of children living in areas with a medium or severe prevalence of fluorosis was lower than that of children living in areas with only slight fluorosis or no fluorosis. The development of intelligence appeared to be adversely affected by fluoride in the areas with a medium or severe prevalence of fluorosis but to a minor extent only in areas with only a slight prevalence of fluorosis. A high fluoride intake was associated with a lower intelligence. No correlation was found between age and intelligence in the areas with a medium and severe prevalence of fluorosis. The effect of exposure to a high level of fluoride on intelligence may occur at an early stage of development of the embryo and infant when the differentiation of brain nerve cells is occurring and development is most rapid.
[Translated by Julian Brooke and published with the permission of the Chinese Journal of Control of Endemic
SUMMARY: 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
Journal of Dental Medicine
2006;19(2) : 80-86
Background and Aim: Human and animal studies linking fluoride with diminished intelligence have been published. Although adverse effects of high intake of fluoride on intelligence and mental acuity continue to be reported, they are still controversial. The aim of this research was to investigate the relationship between fluoride in drinking water and children's intelligence. Materials and Methods: In this cross sectional study, 41 children were selected from the high fluoride area with 2.5mg/l (ppm) fluoride in the drinking water and 85 children were selected from low fluoride area with 0.4mg/l (ppm) fluoride in the drinking water. The intelligence quotient (IQ) of each child was measured by the Raven's test. The history of illnesses affecting the nervous system, head trauma, birth weight (2.5kg or 2.5kg), residental history, age and sex of children were investigated by questionnaires completed by the children's parents. Data were analyzed by Chi-Square test with p