BACKGROUND Lead is toxic to cognitive and behavioral functioning in children even at levels well below those producing physical symptoms. Continuing efforts in the U.S. since about the 1970s to reduce lead exposure in children have dramatically reduced the incidence of elevated blood lead levels (with elevated levels defined by the current U.S. Centers for Disease Control threshold of 10 μg/dl). The current study examines how much lead toxicity continues to impair the academic achievement of children of New York State, using 2010 test data. METHODS This study relies on three sets of data published for the 57 New York counties outside New York City: school achievement data from the New York State Department of Education, data on incidence of elevated blood lead levels from the New York State Department of Health, and data on income from the U.S. Census Bureau. We studied third grade and eighth grade test scores in English Language Arts and mathematics. Using the county as the unit of analysis, we computed bivariate correlations and regression coefficients, with percent of children achieving at the lowest reported level as the dependent variable and the percent of preschoolers in the county with elevated blood lead levels as the independent variable. Then we repeated those analyses using partial correlations to control for possible confounding effects of family income, and using multiple regressions with income included. RESULTS The bivariate correlations between incidence of elevated lead and number of children in the lowest achievement group ranged between 0.38 and 0.47. The partial correlations ranged from 0.29 to 0.40. The regression coefficients, both bivariate and partial (both estimating the increase in percent of children in the lowest achievement group for every percent increase in the children with elevated blood lead levels), ranged from 0.52 to 1.31. All regression coefficients, when rounded to the nearest integer, were approximately 1. Thus, when the percent of children showing elevated lead increases by one percent, the percent of children in the lowest achievement group, according to the regression equations generated, also increases by about one percent. All associations were significant at the 0.05 level. CONCLUSION Despite public health advances, and despite the imprecision of measures, an association between the incidence of elevated blood lead and achievement in New York counties is still apparent, not attributable to confounding by income. Efforts to reduce lead exposure should persist with vigor.

中文翻译：

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铅暴露和 2010 年纽约县儿童的成绩测试分数。

背景铅对儿童的认知和行为功能是有毒的，即使水平远低于产生身体症状的水平。大约自 1970 年代以来，美国为减少儿童铅暴露而做出的持续努力已经显着降低了血铅水平升高的发生率（目前美国疾病控制中心定义的升高水平为 10 μg/dl）。目前的研究使用 2010 年的测试数据检查铅毒性在多大程度上继续损害纽约州儿童的学业成绩。方法 本研究依赖于纽约市以外 57 个纽约县发布的三组数据：来自纽约州教育部的学业成绩数据，来自纽约州卫生部的血铅水平升高发生率数据，和来自美国的收入数据 人口普查局。我们研究了英语语言艺术和数学的三年级和八年级考试成绩。以县为分析单位，我们计算了双变量相关性和回归系数，以达到最低报告水平的儿童百分比作为因变量，以县内血铅水平升高的学龄前儿童百分比作为自变量。然后我们使用偏相关重复这些分析来控制家庭收入可能的混杂影响，并使用包含收入的多元回归。结果 铅含量升高的发生率与成绩最低的组中儿童数量之间的双变量相关范围介于 0.38 和 0.47 之间。偏相关的范围从 0.29 到 0.40。回归系数，双变量和部分变量（均估计血铅水平升高的儿童每增加一个百分比，成绩最低的组中儿童的百分比增加），范围从 0.52 到 1.31。所有回归系数，当四舍五入到最接近的整数时，大约为 1。因此，当铅含量升高的儿童百分比增加 1% 时，根据生成的回归方程，成绩最低组的儿童百分比也增加大约百分之一。所有关联均在 0.05 水平上显着。结论 尽管公共卫生取得了进步，尽管措施不精确，但纽约县血铅升高的发生率与成就之间的关联仍然很明显，不能归因于收入混杂。