IQ and blood lead from 2 to 7 years of age: are the effects in older children the residual of high blood lead concentrations in 2-year-olds?
IQ and blood lead from 2 to 7 years of age: are the effects in older children the residual of high blood lead concentrations in 2-year-olds?
复制标题
DOI：
10.1289/ehp.7625
复制
发表时间：
2005-05
影响因子：
10.4
通讯作者：
Rogan WJ
中科院分区：
文献类型：
--
作者：
Chen A;Dietrich KN;Ware JH;Radcliffe J;Rogan WJ
在美国，18-30个月大时血铅浓度峰值的增加被认为会导致4-6岁时智商得分的降低，此时智商变得稳定和可测量。在波士顿进行的一项前瞻性研究的数据表明，2岁时的血铅浓度比后来的血铅浓度或与智商同时测量的血铅浓度更能预测年龄较大儿童的认知缺陷。因此，学龄儿童血铅和智商之间的横向关联被广泛解释为早期较高血铅浓度的残余影响，或者智力较低的儿童摄入更多含铅粉尘或油漆碎片的趋势，而不是年龄较大的儿童的因果关系。在这里，我们分析了一项临床试验的数据，在该试验中，儿童在大约2岁时接受血铅浓度升高（20-44 μg/dL）的治疗，并通过一系列智商测试和血铅测量进行随访，直到7岁。我们发现，随着儿童年龄的增长，横截面关联的强度增加，而基线血铅和智商之间的关系减弱。因此，血铅峰值水平并不能完全解释年龄较大的儿童血铅浓度较低与智商之间的关系。因此，血液水平对智商的影响可能比目前认为的要大。
Increases in peak blood lead concentrations, which occur at 18–30 months of age in the United States, are thought to result in lower IQ scores at 4–6 years of age, when IQ becomes stable and measurable. Data from a prospective study conducted in Boston suggested that blood lead concentrations at 2 years of age were more predictive of cognitive deficits in older children than were later blood lead concentrations or blood lead concentrations measured concurrently with IQ. Therefore, cross-sectional associations between blood lead and IQ in school-age children have been widely interpreted as the residual effects of higher blood lead concentrations at an earlier age or the tendency of less intelligent children to ingest more leaded dust or paint chips, rather than as a causal relationship in older children. Here we analyze data from a clinical trial in which children were treated for elevated blood lead concentrations (20–44 μg/dL) at about 2 years of age and followed until 7 years of age with serial IQ tests and measurements of blood lead. We found that cross-sectional associations increased in strength as the children became older, whereas the relation between baseline blood lead and IQ attenuated. Peak blood lead level thus does not fully account for the observed association in older children between their lower blood lead concentrations and IQ. The effect of concurrent blood level on IQ may therefore be greater than currently believed.
登录
查看更多内容
影响因子：
2.9
作者：
Wasserman, GA;Liu, X;Graziano, JH
通讯作者：
Graziano, JH
影响因子：
120.7
作者：
RUFF, HA;BIJUR, PE;ROSEN, JF
通讯作者：
ROSEN, JF
影响因子：
158.5
作者：
Canfield, RL;Henderson, CR;Lanphear, BP
通讯作者：
Lanphear, BP
影响因子：
10.4
作者：
Pirkle, JL;Kaufmann, RB;Paschal, DC
通讯作者：
Paschal, DC
影响因子：
120.7
作者：
Tong, S;Baghurst, PA;McMichael, AJ
通讯作者：
McMichael, AJ