Miodovnik Amir, Landrigan Philip J
Children's Environmental Health Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
Environ Health Perspect. 2009 Jul;117(7):1021-2. doi: 10.1289/ehp.0900573. Epub 2009 Mar 25.
Following a recent report of lead in certain commercial vitamin products, the U.S. Food and Drug Administration (FDA) conducted a nationwide survey to determine the Pb content in 324 multivitamin/mineral products labeled for use by women and children. The FDA compared estimated Pb exposures from each product with safe/tolerable exposure levels, termed provisional total tolerable intake (PTTI) levels, previously developed for at-risk population groups in 1992.
We investigated the FDA's conclusions that Pb concentrations in all vitamin products examined do not pose a hazard to health because they are below the PTTI levels for all groups considered.
For their initial estimations of PTTI levels, the FDA used a blood lead level (BLL) of 10 microg/dL as the threshold for adverse effects in children and in pregnant or lactating women. Studies have repeatedly linked chronic exposure to BLLs < 10 microg/dL with impairments in cognitive function and behavior in young children despite the absence of overt signs of toxicity. The FDA analysis also omitted any consideration of nonfood sources of Pb exposure, which is inconsistent with our current understanding of how most children develop elevated BLLs.
We feel that based on these oversights, the FDA's conclusions are unduly reassuring and that reconsideration of their current recommendations appears warranted.
继近期有报道称某些商业维生素产品中含有铅之后，美国食品药品监督管理局（FDA）开展了一项全国性调查，以确定324种标注供妇女和儿童使用的多种维生素/矿物质产品中的铅含量。FDA将每种产品的估计铅暴露量与1992年之前为高危人群制定的安全/可耐受暴露水平（称为暂定总耐受摄入量（PTTI）水平）进行了比较。
我们调查了FDA的结论，即所有检测的维生素产品中的铅浓度不会对健康造成危害，因为它们低于所有被考虑群体的PTTI水平。
FDA在初步估计PTTI水平时，将儿童以及孕妇或哺乳期妇女血铅水平（BLL）10微克/分升作为不良反应的阈值。尽管没有明显的毒性迹象，但研究多次将长期暴露于低于10微克/分升的BLL与幼儿认知功能和行为受损联系起来。FDA的分析还忽略了对非食物来源铅暴露的任何考虑，这与我们目前对大多数儿童血铅水平升高原因的理解不一致。
我们认为，基于这些疏忽，FDA的结论过于令人安心，似乎有必要重新考虑其当前建议。
