Walkowiak J, Altmann L, Krämer U, Sveinsson K, Turfeld M, Weishoff-Houben M, Winneke G
Division of Biological Psychology, Medical Institute of Environmental Hygiene at the Heinrich-Heine-University Düsseldorf, Germany.
Neurotoxicol Teratol. 1998 Sep-Oct;20(5):511-21. doi: 10.1016/s0892-0362(98)00010-5.
Within a larger environmental health screening program neurobehavioral measures were taken in 384 6-year-old children (mean age 74 months) in the cities of Leipzig, Gardelegen, and Duisburg. Lead concentrations in venous blood samples (PbB) and urinary mercury excretion in 24-h samples (HgU) were measured as markers of environmental exposure by electrothermal AAS. Dependent variables included two subtests from the WISC [vocabulary (V) and block design (BD)] as well as five tests from the NES2 [pattern comparison, pattern memory, tapping, simple reaction time, and the continuous performance test (CPT; child version)]. In addition, visual functions [visual acuity (TITMUS-test) and contrast sensitivity (FACT)] were tested as covariates. The overall average PbB (geometric mean) was 42.5 microg/l (upper 95% value = 89 microg/l). The overall average mercury excretion (HgU) was 0.16 microg/24 h. Whereas no significant or borderline associations between HgU and any of the target variables was found, significant negative associations were observed between PbB and verbal intelligence (WISC vocabulary but not WISC Block Design) and false-positive responses (false alarms), as well as false-negative responses (miss) in the CPT. Whereas parental education was the most important confounder for WISC performance, visual contrast sensitivity and computer familiarity also proved predictive for performance in several computer-based NES subtests. It is concluded that non-IQ measures, namely measures of sustained attention, are negatively affected in children with 95% of blood-lead levels below 90 microg/l, even after adjustment for intelligence and contrast sensitivity, whereas the causative role of lead in altering IQ functions remains somewhat equivocal, because important covariates could not be controlled for.
在一项更大规模的环境卫生筛查项目中，对莱比锡、加德莱根和杜伊斯堡市的384名6岁儿童（平均年龄74个月）进行了神经行为测量。通过电热原子吸收光谱法测量静脉血样本中的铅浓度（PbB）和24小时尿液样本中的汞排泄量（HgU），作为环境暴露的指标。因变量包括韦氏儿童智力量表（WISC）的两个子测试[词汇（V）和积木图案（BD）]以及神经行为评估系统第二版（NES2）的五个测试[图案比较、图案记忆、敲击、简单反应时和连续性能测试（CPT；儿童版）]。此外，还测试了视觉功能[视力（TITMUS测试）和对比敏感度（FACT）]作为协变量。总体平均血铅水平（几何平均数）为42.5微克/升（95%上限值 = 89微克/升）。总体平均汞排泄量（HgU）为0.16微克/24小时。虽然未发现HgU与任何目标变量之间存在显著或临界关联，但观察到血铅水平与言语智力（WISC词汇而非WISC积木图案）、假阳性反应（误报）以及CPT中的假阴性反应（漏报）之间存在显著负相关。虽然父母教育程度是WISC表现的最重要混杂因素，但视觉对比敏感度和对计算机的熟悉程度也被证明可预测几个基于计算机的NES子测试的表现。研究得出结论，即使在对智力和对比敏感度进行调整后，血铅水平95%低于90微克/升的儿童的非智商测量指标，即持续注意力测量指标仍受到负面影响，而铅在改变智商功能方面的因果作用仍有些不明确，因为无法控制重要的协变量。
