BACKGROUND Exposure to lead during childhood is detrimental to children's health. The extent to which the association between lead exposure and elementary school academic outcomes varies across geography is not known. OBJECTIVE Estimate associations between blood lead levels (BLLs) and fourth grade standardized test scores in reading and mathematics in North Carolina using models that allow associations between BLL and test scores to vary spatially across communities. METHODS We link geocoded, individual-level, standardized test score data for North Carolina public school students in fourth grade (2013-2016) with detailed birth records and blood lead testing data retrieved from the North Carolina childhood blood lead state registry on samples typically collected at 1-6 y of age. BLLs were categorized as: 1μg/dL (reference), 2μg/dL, 3-4μg/dL and ≥5μg/dL. We then fit spatially varying coefficient models that incorporate information sharing (smoothness), across neighboring communities via a Gaussian Markov random field to provide a global estimate of the association between BLL and test scores, as well as census tract-specific estimates (i.e., spatial coefficients). Models adjusted for maternal- and child-level covariates and were fit separately for reading and math. RESULTS The average BLL across the 91,706 individuals in the analysis dataset was 2.84μg/dL. Individuals were distributed across 2,002 (out of 2,195) census tracts in North Carolina. In models adjusting for child sex, birth weight percentile for gestational age, and Medicaid participation as well as maternal race/ethnicity, educational attainment, marital status, and tobacco use, BLLs of 2μg/dL, 3-4μg/dL and ≥5μg/dL were associated with overall lower reading test scores of -0.28 [95% confidence interval (CI): -0.43, -0.12], -0.53 (-0.69, -0.38), and -0.79 (-0.99, -0.604), respectively. For BLLs of 1μg/dL, 2μg/dL, 3-4μg/dL and ≥5μg/dL, spatial coefficients-that is, tract-specific adjustments in reading test score relative to the "global" coefficient-ranged from -9.70 to 2.52, -3.19 to 3.90, -11.14 to 7.85, and -4.73 to 4.33, respectively. Results for mathematics were similar to those for reading. CONCLUSION The association between lead exposure and reading and mathematics test scores exhibits considerable heterogeneity across North Carolina communities. These results emphasize the need for prevention and mitigation efforts with respect to lead exposures everywhere, with special attention to locations where the cognitive impact is elevated. https://doi.org/10.1289/EHP13898.

中文翻译：

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北卡罗来纳州公立学校四年级学生早期儿童铅暴露与标准化考试成绩之间关系的空间变异性（2013-2016）。


背景技术童年时期接触铅对儿童的健康有害。铅暴露与小学学业成绩之间的关联程度因地区而异尚不清楚。目标 使用允许 BLL 与考试成绩之间的关联在不同社区之间存在空间差异的模型，估计北卡罗来纳州血铅水平 (BLL) 与四年级阅读和数学标准化考试成绩之间的关联。方法 我们将北卡罗来纳州公立学校四年级学生（2013-2016 年）的地理编码、个人水平、标准化测试成绩数据与从北卡罗来纳州儿童血铅州登记处检索的详细出生记录和血铅检测数据联系起来，这些数据通常收集样本1-6岁。 BLL 分为：1μg/dL（参考）、2μg/dL、3-4μg/dL 和 ≥5μg/dL。然后，我们通过高斯马尔可夫随机场拟合包含信息共享（平滑度）的空间变化系数模型，以提供 BLL 和测试分数之间关联的全局估计，以及人口普查区域特定的估计（即空间系数）。模型针对母亲和儿童水平的协变量进行了调整，并分别适合阅读和数学。结果 分析数据集中 91,706 名个体的平均 BLL 为 2.84μg/dL。个人分布在北卡罗来纳州 2,002 个人口普查区（共 2,195 个）。在调整儿童性别、胎龄出生体重百分位、医疗补助参与以及母亲种族/民族、教育程度、婚姻状况和烟草使用的模型中，BLL 为 2μg/dL、3-4μg/dL 和 ≥5μg/ dL 与整体较低的阅读测试分数 -0 相关。28 [95% 置信区间 (CI)：-0.43、-0.12]、-0.53 (-0.69、-0.38) 和 -0.79 (-0.99、-0.604)。对于 1μg/dL、2μg/dL、3-4μg/dL 和 ≥5μg/dL 的 BLL，空间系数（即阅读测试分数相对于“全局”系数的特定区域调整）范围为 -9.70 至 2.52 、-3.19 至 3.90、-11.14 至 7.85 和 -4.73 至 4.33。数学成绩与阅读成绩相似。结论 铅暴露与阅读和数学考试成绩之间的关联在北卡罗来纳州各社区表现出相当大的异质性。这些结果强调需要针对各地的铅暴露采取预防和缓解措施，特别关注认知影响较高的地区。 https://doi.org/10.1289/EHP13898。