Shih R A, Glass T A, Bandeen-Roche K, Carlson M C, Bolla K I, Todd A C, Schwartz B S
Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
Neurology. 2006 Nov 14;67(9):1556-62. doi: 10.1212/01.wnl.0000239836.26142.c5. Epub 2006 Sep 13.
To determine if long-term exposure to high levels of lead in the environment is associated with decrements in cognitive ability in older Americans.
We completed a cross-sectional analysis using multiple linear regression to evaluate associations of recent (in blood) and cumulative (in tibia) lead dose with cognitive function in 991 sociodemographically diverse, community-dwelling adults, aged 50 to 70 years, randomly selected from 65 contiguous neighborhoods in Baltimore, MD. Tibia lead was measured with (109)Cd induced K-shell X-ray fluorescence. Seven summary measures of cognitive function were created based on standard tests in these domains: language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory, and visuoconstruction.
The mean (SD) blood lead level was 3.5 (2.2) microg/dL and tibia lead level was 18.7 (11.2) microg/g. Higher tibia lead levels were consistently associated with worse cognitive function in all seven domains after adjusting for age, sex, APOE-epsilon4, and testing technician (six domains p <or= 0.01, one domain p <or= 0.05). Blood lead was not associated with any cognitive domain. Associations with tibia lead were attenuated after adjustment for years of education, wealth, and race/ethnicity.
Independent of recent lead dose, retained cumulative dose resulting from previous environmental exposures may have persistent effects on cognitive function. A portion of age-related decrements in cognitive function in this population may be associated with earlier lead exposure.
确定长期暴露于环境中的高铅水平是否与美国老年人认知能力下降有关。
我们进行了一项横断面分析，使用多元线性回归来评估991名年龄在50至70岁之间、社会人口统计学特征各异的社区居住成年人的近期（血液中）和累积（胫骨中）铅剂量与认知功能之间的关联。这些成年人是从马里兰州巴尔的摩市65个相邻社区中随机选取的。胫骨铅含量通过（109）镉诱导的K层X射线荧光法进行测量。基于这些领域的标准测试创建了七个认知功能综合指标：语言、处理速度、眼手协调、执行功能、言语记忆与学习、视觉记忆和视觉构建。
平均（标准差）血铅水平为3.5（2.2）微克/分升，胫骨铅水平为18.7（11.2）微克/克。在调整年龄、性别、APOE-ε4和测试技术员后，较高的胫骨铅水平在所有七个领域中均与较差的认知功能持续相关（六个领域p≤0.01，一个领域p≤0.05）。血铅与任何认知领域均无关联。在调整教育年限、财富和种族/民族后，与胫骨铅的关联减弱。
独立于近期铅剂量，先前环境暴露导致的累积保留剂量可能对认知功能产生持续影响。该人群中与年龄相关的认知功能下降部分可能与早期铅暴露有关。
