Faculty of Health, York University, Toronto, Ontario, Canada.
Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
Environ Res. 2022 Aug;211:112993. doi: 10.1016/j.envres.2022.112993. Epub 2022 Mar 9.
Prenatal exposure to fluoride has been associated with adverse neurodevelopmental outcomes. However, the neuropsychological profile of fluoride's developmental neurotoxicity at low levels and the stability of this relationship across childhood has not been characterized. We investigated the longitudinal and domain specific effect of prenatal fluoride exposure on IQ among children ages 4, 5, and 6-12 years in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort.
We measured the average of maternal urinary fluoride at each trimester of pregnancy adjusted for creatinine (MUF). Children were administered the McCarthy Scales of Children's Abilities at ages 4 (N = 386) and 5 (N = 308), and the Wechsler Abbreviated Scale of Intelligence at age 6-12 (N = 278). We used generalized estimating equation (GEE) models to estimate the population averaged effect of MUF concentration on longitudinal General Cognitive Index (GCI)/Full-Scale IQ (FSIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) scores (N = 348). We tested for possible interactions between MUF and child sex as well as for MUF and time point on children's IQ. All models controlled for relevant available covariates.
The mean/median MUF concentration was 0.90/0.83 mg/L (SD = 0.39; IQR, 0.64-1.11 mg/L). A 0.5 mg/L increase in MUF predicted an average 2.12-point decrease in GCI/FSIQ (95% CI: -3.49, -0.75) and 2.63-point decrease in PIQ (95% CI: -3.87, -1.40). MUF was marginally associated with VIQ across time (B = -1.29, 95% CI: -2.60, 0.01). No interactions between MUF and child sex or MUF and time were observed.
The negative association between prenatal fluoride exposure and longitudinal IQ was driven by decrements in non-verbal intelligence (i.e. PIQ), suggesting that visual-spatial and perceptual reasoning abilities may be more impacted by prenatal fluoride exposure as compared to verbal abilities.
产前氟暴露与不良神经发育结局有关。然而，低水平氟化物发育神经毒性的神经心理学特征以及这种关系在整个儿童期的稳定性尚未确定。我们在环境毒物暴露于墨西哥的生命早期队列（ELEMENT）中，研究了产前氟暴露对 4、5 和 6-12 岁儿童智商的纵向和特定领域影响。
我们测量了每个孕期的平均母体尿氟水平（经肌酐调整）（MUF）。在 4 岁（N=386）和 5 岁（N=308）时，对儿童进行了麦卡锡儿童能力量表测试，在 6-12 岁时（N=278）进行了韦氏简明智力量表测试。我们使用广义估计方程（GEE）模型来估计 MUF 浓度对纵向一般认知指数（GCI）/全量表智商（FSIQ）、言语智商（VIQ）和表现智商（PIQ）得分的人群平均效应（N=348）。我们测试了 MUF 与儿童性别以及 MUF 与儿童智商时间点之间的可能相互作用。所有模型均控制了相关的可用协变量。
MUF 的平均值/中位数浓度为 0.90/0.83mg/L（SD=0.39；IQR，0.64-1.11mg/L）。MUF 增加 0.5mg/L 预测 GCI/FSIQ 平均降低 2.12 分（95%CI：-3.49，-0.75）和 PIQ 降低 2.63 分（95%CI：-3.87，-1.40）。MUF 与时间呈边缘相关（B=-1.29，95%CI：-2.60，0.01）。未观察到 MUF 与儿童性别或 MUF 与时间之间的相互作用。
产前氟暴露与纵向智商之间的负相关关系是由非言语智力（即 PIQ）下降驱动的，这表明视觉空间和感知推理能力可能比言语能力更容易受到产前氟暴露的影响。
