Children's Environmental Health Initiative, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
Neurotoxicology. 2009 Nov;30(6):1019-24. doi: 10.1016/j.neuro.2009.07.012. Epub 2009 Jul 28.
Extensive research shows that blacks, those of low socioeconomic status, and other disadvantaged groups continue to exhibit poorer school performance compared with middle and upper-class whites in the United States' educational system. Environmental exposures may contribute to the observed achievement gap. In particular, childhood lead exposure has been linked to a number of adverse cognitive outcomes. In previous work, we demonstrated a relationship between early childhood lead exposure and end-of-grade (EOG) test scores on a limited dataset. In this analysis, data from the North Carolina Childhood Lead Poisoning Prevention Program surveillance registry were linked to educational outcomes available through the North Carolina Education Research Data Center for all 100 counties in NC. Our objectives were to confirm the earlier study results in a larger population-level database, determine whether there are differences in the impact of lead across the EOG distribution, and elucidate the impact of cumulative childhood social and environmental stress on educational outcomes. Multivariate and quantile regression techniques were employed. We find that early childhood lead exposure is associated with lower performance on reading EOG test scores in a clear dose-response pattern, with the effects increasingly more pronounced in moving from the high end to the low end of the test score distribution. Parental educational attainment and family poverty status also affect EOG test scores, in a similar dose-response fashion, with the effects again most pronounced at the low end of the EOG test score distribution. The effects of environmental and social stressors (especially as they stretch out the lower tail of the EOG distribution) demonstrate the particular vulnerabilities of socioeconomically and environmentally disadvantaged children. Given the higher average lead exposure experienced by African American children in the United States, lead does in fact explain part of the achievement gap.
大量研究表明，在美国的教育体系中，与中上层阶级的白人相比，黑人、社会经济地位较低的人群和其他弱势群体的在校表现仍然较差。环境暴露可能是造成这种成绩差距的原因之一。特别是，儿童期铅暴露与许多不良认知结果有关。在之前的工作中，我们在一个有限的数据集上证明了儿童早期铅暴露与年级末（EOG）考试成绩之间存在关系。在这项分析中，北卡罗来纳州儿童铅中毒预防计划监测登记处的数据与北卡罗来纳州教育研究数据中心提供的所有 100 个县的教育成果相关联。我们的目标是在更大的人群水平数据库中确认早期研究结果，确定铅对 EOG 分布的影响是否存在差异，并阐明儿童期社会和环境压力对教育成果的影响。我们采用了多元和分位数回归技术。我们发现，儿童早期铅暴露与阅读 EOG 考试成绩呈明显的剂量反应模式，随着成绩从高分端向低分段移动，影响越来越明显。父母的教育程度和家庭贫困状况也会影响 EOG 考试成绩，其影响也以类似的剂量反应模式出现，其影响在 EOG 考试成绩分布的低分段最为明显。环境和社会压力源的影响（尤其是在延伸 EOG 分布的低端时）表明，社会经济和环境处于不利地位的儿童特别脆弱。鉴于美国非裔美国儿童的平均铅暴露水平较高，铅确实在一定程度上解释了成绩差距的部分原因。
