Children's Hospital Boston, Farley Basement Box 127, 300 Longwood Avenue, Boston, MA 02115, USA.
Int J Environ Res Public Health. 2011 Jul;8(7):2593-628. doi: 10.3390/ijerph8072593. Epub 2011 Jun 27.
Many times in the history of lead toxicology the view that "the problem" has been solved and is no longer a major health concern has prevailed, only to have further research demonstrate the prematurity of this judgment. In the last decade, an extraordinary amount of new research on lead has illustrated, all too clearly, that "the problem" has not disappeared, and that, in fact, it has dimensions never before considered. Recent risk assessments have concluded that research has yet to identify a threshold level below which lead can be considered "safe." Although children's intelligence has traditionally been considered to be the most sensitive endpoint, and used as the basis for risk assessment and standard setting, increased lead exposure has been associated with a wide variety of other morbidities both in children and adults, in some cases at biomarker levels comparable to those associated with IQ deficits in children. In adults, these endpoints include all-cause mortality and dysfunctions in the renal, cardiovascular, reproductive, central nervous systems. In children, IQ deficits are observed at blood lead levels well below 10 μg/dL, and the dose-effect relationship appears to be supra-linear. Other health endpoints associated with greater early-life lead exposure in children include ADHD, conduct disorder, aggression and delinquency, impaired dental health, and delayed sexual maturation. Studies employing neuroimaging modalities such as volumetric, diffusion tensor, and functional MRI are providing insights into the neural bases of the cognitive impairments associated with greater lead exposure.
在铅毒理学的历史上，许多时候人们认为“问题”已经得到解决，不再是主要的健康关注点，但进一步的研究表明，这种判断为时过早。在过去的十年中，大量关于铅的新研究非常清楚地表明，“问题”并没有消失，实际上，它的影响范围是以前从未考虑过的。最近的风险评估得出的结论是，研究尚未确定可以认为铅“安全”的阈值水平。尽管儿童的智力一直被认为是最敏感的终点，并被用作风险评估和标准制定的基础，但在儿童和成人中，越来越多的铅暴露与各种各样的其他疾病有关，在某些情况下，其生物标志物水平与儿童智商缺陷相关的水平相当。在成年人中，这些终点包括全因死亡率和肾脏、心血管、生殖、中枢神经系统的功能障碍。在儿童中，智商缺陷在血铅水平低于 10μg/dL 时就观察到，且剂量-效应关系似乎呈超线性。与儿童早期铅暴露程度更大相关的其他健康终点包括注意力缺陷多动障碍、品行障碍、攻击行为和犯罪行为、牙齿健康受损以及性成熟延迟。使用容积成像、弥散张量成像和功能 MRI 等神经影像学方法的研究为与更大程度的铅暴露相关的认知障碍的神经基础提供了深入了解。
