碘缺乏、补碘、高碘对儿童智力影响的Meta分析

Meta-analysis on the relationship between children's intelligence and factors as iodine deficiency,supplement iodine and excessive iodine

目的 量化分析碘缺乏、补碘、高碘对儿童智力的影响。方法 采用Meta分析 ,利用检索工具收集尽可能多的文献。纳入研究的标准是 :研究来自碘缺乏病区或高碘地区、文献采取对照实验设计、提及研究组与对照组的社会经济文化发展水平相近。纳入研究归入碘缺乏、补碘和高碘三个组。结果 纳入碘缺乏、补碘和高碘三组的研究分别为 6 2、36、30项 ,三组内各单项研究的Hunter齐性检验没有显著的统计学意义 (P >0 .0 5 ) ,合并计算的平均效应值依次是 0 .6 9(10 .4个智商分 ,95 %CI =9.9～ 10 .9)、0 .81(12 .2个智商分 ,95 %CI=11.5～ 12 .9)和 0 .2 1(3.2个智商分 ,95 %CI=2 .5～ 4 .0 )。结论 碘缺乏和补碘对病区儿童智力干预作用明显或极为明显 ;碘缺乏造成儿童智商损失约 10分 ,在脑发育关键期补碘出生的儿童智商比未补碘儿童高约 12分 ;

Objective To estimate the role and extent of iodine deficiency, iodine supplement and iodine excess on mental development of children. Methods Meta analysis was applied to study 128 independent items from 63 published and non published papers and reports. The standards of references collected included: age of sample declared by references was 5 15; belong to comparison study; children lived in iodine deficiency disorders (IDD) and iodine excess areas;no difference of social economic and culture development level bettween the study group and the control group. Results Sixty seven percent and 79% of the reports mainly involved severe IDD areas respectively. Hunter test of each studies, i.e. iodine deficiency, iodine supplement and excessive iodine group had not discovered statistic difference at the level of α= 0.05 . The weighted average ES of damage affecting on children's intelligence by iodine deficiency achieved 0.69 , which was equivalent to a marked drop in 10.4 IQ points [95% confidence interval ( CI ): 9.9 10.9 ] when comparing with the children living under non IDD. The weighted average ES of protective effect on children's intelligence by iodine supplement reached 0.81 , which meant that the IQ of children born after correction of iodine deficiency increased 12.2 points (95% CI : 11.5 12.9 ) in comparison with those born at least one year before the correction of iodine deficiency.Most of the references about the relationship between iodine excess and intelligence were gathered from proceedings, while the others were from journals. They location were in some areas of Shandong, Hebei, Shanxi and Inner Mongolia. The mean ES of the role of iodine excess on intelligence was 0.21 , which was corresponding to 3.2 IQ points (95% CI : 2.5 4.0 ).Conclusion 1)Iodine deficiency played a role of intermediate strength compared with other causes in delaying brain development making children to be at least 10 IQ points loss in IDD areas. 2)Effective iodine supplement plays a remarkable strengthing role in promoting brain development and can cause 12 IQ points increase for children who were born after the correction of iodine status. 3)Iodine excess has not shown significant important role in children's intelligence.