California Department of Public Health, MS 7208, 1616 Capitol Ave, Sacramento, CA 95814, USA.
ECU School of Dental Medicine, 1851 MacGregor Downs Road - MS 701, East Carolina University, Greenville, NC 27834-4354, USA.
Public Health. 2023 Jun;219:73-84. doi: 10.1016/j.puhe.2023.03.011. Epub 2023 Apr 28.
Previous meta-analyses have mainly focused on studies conducted in endemic fluorosis areas with relatively high fluoride concentrations. These are impoverished rural communities in China, India, and Iran, and the findings cannot be generalised to developed countries. Therefore, we investigated the association between fluoride concentrations relevant to community water fluoridation and children's cognition measured with IQ scores by synthesising effect sizes reported in observational studies.
A previous meta-analysis and the National Toxicology Program database that included a search of multiple databases and the authors' search of PubMed, Google Scholar, and Mendeley provided the data. Cross-sectional and cohort studies examining the association between fluoride and children's cognition and intelligence scores were selected. Two reviewers abstracted data using standard procedures. We performed three meta-analyses to synthesise the effects using the random effects models.
Eight studies of standardized mean difference in IQ scores from non-endemic fluorosis areas found no statistically significant difference between recommended and lower levels of fluoride (standardized mean difference = 0.07; 95% confidence interval: -0.02, 0.17; I = 0%), and no significant fluctuation in IQ scores across the differences in fluoride concentrations by non-linear modeling with restricted cubic spline (P = 0.21). Meta-analyses of children's and maternal spot urinary fluoride associated pooled regression coefficients (Beta = 0.16; 95% confidence interval: -0.40, 0.73; P = 0.57; I = 0%, Beta = -0.92; 95% CI: -3.29, 1.46; P = 0.45; I = 72%) were not statistically significant. Further regression analysis by standardizing absolute mean IQ scores from lower fluoride areas did not show a relationship between F concentration and IQ scores (Model Likelihood-ratio test: P-value = 0.34.) CONCLUSIONS: These meta-analyses show that fluoride exposure relevant to community water fluoridation is not associated with lower IQ scores in children. However, the reported association observed at higher fluoride levels in endemic areas requires further investigation.
以前的荟萃分析主要集中在氟中毒流行地区进行的研究，这些地区的氟浓度相对较高。这些地区是中国、印度和伊朗的贫困农村社区，研究结果不能推广到发达国家。因此，我们通过综合观察性研究报告的效应大小，研究了与社区饮水氟化相关的氟浓度与儿童认知能力（以智商分数衡量）之间的关系。
一项先前的荟萃分析和国家毒理学计划数据库，包括对多个数据库的搜索以及作者对 PubMed、Google Scholar 和 Mendeley 的搜索，提供了数据。选择了研究氟化物与儿童认知和智力评分之间关系的横断面和队列研究。两位审查员使用标准程序提取数据。我们使用随机效应模型进行了三项荟萃分析来综合效应。
八项来自非氟中毒流行地区的智商分数标准化均数差异的研究发现，推荐水平和较低水平的氟化物之间没有统计学上的显著差异（标准化均数差异=0.07；95%置信区间：-0.02，0.17；I=0%），并且非线性建模中氟化物浓度差异与智商分数之间没有明显波动，限制立方样条（P=0.21）。儿童和母亲点尿氟相关的汇总回归系数（Beta=0.16；95%置信区间：-0.40，0.73；P=0.57；I=0%，Beta=-0.92；95%置信区间：-3.29，1.46；P=0.45；I=72%）的荟萃分析结果无统计学意义。通过标准化低氟地区的绝对平均智商分数进行进一步回归分析，也未显示 F 浓度与智商分数之间存在关系（模型似然比检验：P 值=0.34）。
这些荟萃分析表明，与社区饮水氟化相关的氟暴露与儿童较低的智商分数无关。然而，在氟中毒流行地区观察到的更高氟水平下的报告关联需要进一步研究。
