2020 China - IQ & Dental Fluorosis

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2020 China - IQ & Dental Fluorosis

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Lou D, Luo Y, Liu J, Zheng D, Ma R, Chen F, Yu Y, Guan Z - "Refinement Impairments of Verbal-Performance Intelligent Quotient in Children Exposed to Fluoride Produced by Coal Burning" Biol Trace Elem Res (2020) doi: 10.1007/s12011-020-02174-z. Epub ahead of print. PMID: 32363519.

To explore the relationship between total intelligence quotient (IQ), verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ), and fluoride exposure in children aged 8-12 years in coal-burning fluorosis area of Dafang County, Guizhou Province, China. The Wechsler Intelligence Scale for Children Revised in China (WISC-CR) was used to test the total IQ, VIQ, and PIQ in 99 children aged 8-12 years (55 in dental fluorosis group and 44 in control group). The differences in the intellectual levels between the two groups were compared, and the correlation between the intellectual level of children exposed to fluoride and the exposure dose of fluoride was analyzed. The VIQ, PIQ, and total IQ in the dental fluorosis group were 85.64 ± 16.53, 94.87 ± 12.73, and 88.51 ± 12.77, respectively, and these were lower than those in the control group (94.34 ± 16.04, 99.23 ± 12.44, and 96.64 ± 11.70, respectively). Significant difference was observed in VIQ and total IQ between the two groups (P = 0.002, P = 0.01), but not in the PIQ (P > 0.05). Each item of VIQ impairment (common sense, similar, arithmetic, vocabulary, and understanding) was significantly lower than those without VIQ impairment in the dental fluorosis group (P < 0.05). There was a significant difference in two items of building blocks and decoding between PIQ impairment and normal group (P < 0.05). Children with fluorosis in coal-burning areas had impaired IQ and obviously had impaired VIQ. Thus, the language learning ability should be strengthened in children exposed to fluorosis.
Last edited by pfpcnews on Mon Nov 30, 2020 4:14 pm, edited 1 time in total.
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2018 China - IQ & Dental Fluorosis

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Yu X, Chen J, Li Y, Liu H, Hou C, Zeng Q, Cui Y, Zhao L, Li P, Zhou Z, Pang S, Tang S, Tian K, Zhao Q, Dong L, Xu C, Zhang X, Zhang S, Liu L, Wang A - "Threshold effects of moderately excessive fluoride exposure on children's health: A potential association between dental fluorosis and loss of excellent intelligence" 118:116-124 (2018) doi: 10.1016/j.envint.2018.05.042. Epub 2018 Jun 2. PMID: 29870912

Background: Excessive fluoride exposure is associated with adverse health outcomes, but little is known of the effects of moderately chronic fluoride exposure on children's health.

Objectives: We conducted a cross-sectional study to explore the health impact of moderately excessive fluoride in drinking water.

Methods: We recruited 2886 resident children, aged 7 to 13 years, randomly from endemic and non-endemic fluorosis areas in Tianjin, China. The fluoride levels in drinking water and urine were measured using the national standardized ion selective electrode method. We examined the dose-response effects of low-to-moderate fluoride exposure on dental fluorosis (DF) and intelligence quotient (IQ), and evaluated the potential relationships between DF grades and intelligence levels using piecewise linear regression and multiple logistic regression, respectively.

Results: The adjusted odds ratios (ORs) of DF were 2.24 (95% confidence interval [CI]: 2.02 to 2.48) for every 0.1 mg/L increment in the water fluoride concentration in the range of 0.80 to 1.50 mg/L, and 2.61 (95% CI: 2.32 to 2.93) for every 0.5 mg/L increment in the urinary fluoride level up to 1.80 mg/L. Every 0.5 mg/L increment in the water fluoride level was associated with a reduction of 4.29 in the IQ score (95% CI: -8.09 to -0.48) in the range of 3.40 to 3.90 mg/L, and a decreased probability of developing excellent intelligence (IQ ≥ 130, OR = 0.60, 95% CI: 0.47 to 0.77) in the range of 0.20-1.40 mg/L, respectively. Every 0.5 mg/L increment in the urinary fluoride level was related to a decrease of 2.67 in the IQ scores (95% CI: -4.67 to -0.68) between 1.60 mg/L to 2.50 mg/L. Excellent intelligence decreased by 51% in children with higher urinary fluoride, and by 30% with each degree increment of DF.

Conclusions: Our study suggests threshold and saturation effects of moderately excessive fluoride exposure on DF and intelligence loss in children, and a potential association between DF and the loss of excellent intelligence.

Keywords: Dental fluorosis; Fluoride; Intelligence loss; Threshold effect.
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