Department of Preventive Medicine, Mount Sinai School of Medicine, NY, USA.
Environ Res. 2012 Oct;118:65-71. doi: 10.1016/j.envres.2012.08.003. Epub 2012 Aug 24.
Pediatric lead (Pb) exposure impacts cognitive function and behavior and co-exposure to manganese (Mn) may enhance neurotoxicity.
To assess cognitive and behavioral function in adolescents with environmental exposure to Pb and Mn.
In this cross sectional study, cognitive function and behavior were examined in healthy adolescents with environmental exposure to metals. The Wechsler Intelligence Scale for Children (WISC) and the Conners-Wells' Adolescent Self-Report Scale Long Form (CASS:L) were used to assess cognitive and behavioral function, respectively. ALAD polymorphisms rs1800435 and rs1139488 were measured as potential modifiers.
We examined 299 adolescents (49.2% females) aged 11-14 years. Blood lead (BPb) averaged 1.71 μg/dL (median 1.5, range 0.44-10.2), mean Blood Manganese (BMn) was 11.1 μg/dL (median 10.9, range 4.00-24.1). Average total IQ was 106.3 (verbal IQ=102, performance IQ=109.3). According to a multiple regression model considering the effect of other covariates, a reduction of about 2.4 IQ points resulted from a two-fold increase of BPb. The Benchmark Level of BPb associated with a loss of 1 IQ-point (BML01) was 0.19 μg/dL, with a lower 95% confidence limit (BMLL01) of 0.11 μg/dL. A very weak correlation resulted between BPb and the ADHD-like behavior (Kendall's tau rank correlation=0.074, p=0.07). No influence of ALAD genotype was observed on any outcome. Manganese was not associated with cognitive and behavioral outcomes, nor was there any interaction with lead.
These findings demonstrate that very low level of lead exposure has a significant negative impact on cognitive function in adolescent children. Being an essential micro-nutrient, manganese may not cause cognitive effects at these low exposure levels.
儿童铅（Pb）暴露会影响认知功能和行为，而同时暴露于锰（Mn）可能会增强其神经毒性。
评估环境中 Pb 和 Mn 暴露的青少年的认知和行为功能。
在这项横断面研究中，我们检查了环境金属暴露的健康青少年的认知功能和行为。使用韦氏儿童智力量表（WISC）和康纳斯-威尔斯青少年自我报告量表长式（CASS：L）分别评估认知和行为功能。ALAD 多态性 rs1800435 和 rs1139488 被测量为潜在的修饰物。
我们检查了 299 名 11-14 岁的青少年（49.2%为女性）。平均血铅（BPb）为 1.71μg/dL（中位数为 1.5，范围为 0.44-10.2），平均血锰（BMn）为 11.1μg/dL（中位数为 10.9，范围为 4.00-24.1）。平均总智商为 106.3（言语智商=102，操作智商=109.3）。根据考虑其他协变量影响的多元回归模型，BPb 增加一倍会导致智商降低约 2.4 个点。与智商降低 1 个点相关的 BPb 基准水平（BML01）为 0.19μg/dL，其置信度下限（BMLL01）为 0.11μg/dL。BPb 与 ADHD 样行为之间存在非常弱的相关性（肯德尔等级相关系数=0.074，p=0.07）。ALAD 基因型对任何结果均无影响。锰与认知和行为结果无关，与铅也没有相互作用。
这些发现表明，极低水平的铅暴露对青少年儿童的认知功能有显著的负面影响。作为一种必需的微量元素，锰在这些低暴露水平下可能不会产生认知影响。
