불소충치예방은 안전한가?

불소의 신경독성: 뇌발달, IQ와의 관계

어린이와 임신부, 태아가 불소를 조심해야 하는 이유~

과도한 불소노출은 치아불소증과 골격불소증의 위험을 높일 뿐아니라 뇌발달, 신장질환과도 깊은 관련이 있습니다. 아래 최근의 논문들은 불소섭취와 태아의 뇌발달과의 관계에 관한 연구들입니다.

물론, 충치예방을 위한 미량의 불소로 이런 증상이 생기는 것은 아니지만 물, 공기, 흙이 불소에 의해 오염 되었다면 개인이 얼마나 많은 불소를 평생 섭취하게 되는지는 알 수가 없습니다. (이는 노후의 골격불소증과 깊은 관련이 있습니다)

2018 Jan;154:87-97.

doi: 10.1016/j.puhe.2017.08.013. Epub 2017 Dec 22.

Association between water fluoride and the level of children's intelligence: a dose-response meta-analysis

Q Duan  ¹ , J Jiao  ¹ , X Chen  ¹ , X Wang  ²

Abstract

Objectives: Higher fluoride concentrations in water have inconsistently been associated with the levels of intelligence in children. The following study summarizes the available evidence regarding the strength of association between fluoridated water and children's intelligence.

Study design: Meta-analysis.

Methods: PubMed, Embase, and Cochrane Library databases were systematically analyzed from November 2016. Observational studies that have reported on intelligence levels in relation to high and low water fluoride contents, with 95% confidence intervals (CIs) were included. Further, the results were pooled using inverse variance methods. The correlation between water fluoride concentration and intelligence level was assessed by a dose-response meta-analysis.

Results: Twenty-six studies reporting data on 7258 children were included. The summary results indicated that high water fluoride exposure was associated with lower intelligence levels (standardized mean difference : -0.52; 95% CI: -0.62 to -0.42; P < 0.001). The findings from subgroup analyses were consistent with those from overall analysis. The dose-response meta-analysis suggested a significant association between water fluoride dosage and intelligence (P < 0.001), while increased water fluoride exposure was associated with reduced intelligence levels.

Conclusions: Greater exposure to high levels of fluoride in water was significantly associated with reduced levels of intelligence in children. Therefore, water quality and exposure to fluoride in water should be controlled in areas with high fluoride levels in water.

Keywords: Children; Intelligence; Meta-analysis; Water fluoride.

2020 Jan;134:105315.

doi: 10.1016/j.envint.2019.105315. Epub 2019 Nov 16.

Fluoride exposure from infant formula and child IQ in a Canadian birth cohort

Christine Till  ¹ , Rivka Green  ² , David Flora  ² , Richard Hornung  ³ , E Angeles Martinez-Mier  ⁴ , Maddy Blazer  ² , Linda Farmus  ² , Pierre Ayotte  ⁵ , Gina Muckle  ⁶ , Bruce Lanphear  ⁷

Abstract

Background: Infant consumption of formula reconstituted with fluoridated water can lead to excessive fluoride intake. We examined the association between fluoride exposure in infancy and intellectual ability in children who lived in fluoridated or non-fluoridated cities in Canada.

Methods: We examined 398 mother-child dyads in the Maternal-Infant Research on Environmental Chemicals cohort who reported drinking tap water. We estimated water fluoride concentration using municipal water reports. We used linear regression to analyze the association between fluoride exposure and IQ scores, measured by the Wechsler Primary and Preschool Scale of Intelligence-III at 3-4 years. We examined whether feeding status (breast-fed versus formula-fed) modified the impact of water fluoride and if fluoride exposure during fetal development attenuated this effect. A second model estimated the association between fluoride intake from formula and child IQ.

Results: Thirty-eight percent of mother-child dyads lived in fluoridated communities. An increase of 0.5 mg/L in water fluoride concentration (approximately equaling the difference between fluoridated and non-fluoridated regions) corresponded to a 9.3- and 6.2-point decrement in Performance IQ among formula-fed (95% CI: -13.77, -4.76) and breast-fed children (95% CI: -10.45, -1.94). The association between water fluoride concentration and Performance IQ remained significant after controlling for fetal fluoride exposure among formula-fed (B = -7.93, 95% CI: -12.84, -3.01) and breastfed children (B = -6.30, 95% CI: -10.92, -1.68). A 0.5 mg increase in fluoride intake from infant formula corresponded to an 8.8-point decrement in Performance IQ (95% CI: -14.18, -3.34) and this association remained significant after controlling for fetal fluoride exposure (B = -7.62, 95% CI: -13.64, -1.60).

Conclusions: Exposure to increasing levels of fluoride in tap water was associated with diminished non-verbal intellectual abilities; the effect was more pronounced among formula-fed children.

Keywords: Fluoride; Formula; Infants; Intellectual function; Water fluoridation

2017 Sep 19;125(9):097017.

doi: 10.1289/EHP655.

Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico

Morteza Bashash  ¹ , Deena Thomas  ² , Howard Hu  ¹ , E Angeles Martinez-Mier  ³ , Brisa N Sanchez  ² , Niladri Basu  ⁴ , Karen E Peterson  ^{2   5   6} , Adrienne S Ettinger  ² , Robert Wright  ⁷ , Zhenzhen Zhang  ² , Yun Liu  ² , Lourdes Schnaas  ⁸ , Adriana Mercado-García  ⁹ , Martha María Téllez-Rojo  ⁹ , Mauricio Hernández-Avila  ⁹

Abstract

Background: Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants.

Objective: Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development.

Methods: We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6-12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children's Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6-12.

Results: We had complete data on 299 mother-child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: -5.42, -0.87) and 2.50 (95% CI -4.12, -0.59) lower offspring GCI and IQ scores, respectively.

Conclusions: In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6-12 y. https://doi.org/10.1289/EHP655.