Department of Clinical Nutrition 425 TOB, Rush University Medical Center, 1700 West Van Buren St., Chicago, IL 60612, USA.
Neurology. 2011 Sep 27;77(13):1276-82. doi: 10.1212/WNL.0b013e3182315a33.
To investigate the interrelations of serum vitamin B12 markers with brain volumes, cerebral infarcts, and performance in different cognitive domains in a biracial population sample cross-sectionally.
In 121 community-dwelling participants of the Chicago Health and Aging Project, serum markers of vitamin B12 status were related to summary measures of neuropsychological tests of 5 cognitive domains and brain MRI measures obtained on average 4.6 years later among 121 older adults.
Concentrations of all vitamin B12-related markers, but not serum vitamin B12 itself, were associated with global cognitive function and with total brain volume. Methylmalonate levels were associated with poorer episodic memory and perceptual speed, and cystathionine and 2-methylcitrate with poorer episodic and semantic memory. Homocysteine concentrations were associated with decreased total brain volume. The homocysteine-global cognition effect was modified and no longer statistically significant with adjustment for white matter volume or cerebral infarcts. The methylmalonate-global cognition effect was modified and no longer significant with adjustment for total brain volume.
Methylmalonate, a specific marker of B12 deficiency, may affect cognition by reducing total brain volume whereas the effect of homocysteine (nonspecific to vitamin B12 deficiency) on cognitive performance may be mediated through increased white matter hyperintensity and cerebral infarcts. Vitamin B12 status may affect the brain through multiple mechanisms.
在一个跨种族的人群样本中，横断面研究血清维生素 B12 标志物与脑容量、脑梗死和不同认知领域表现之间的相互关系。
在芝加哥健康与衰老项目的 121 名社区居住参与者中，维生素 B12 状态的血清标志物与 5 个认知领域的神经心理学测试的综合指标以及平均 4.6 年后获得的大脑 MRI 测量值相关。
所有与维生素 B12 相关的标志物浓度，而不是血清维生素 B12 本身，与整体认知功能和总脑容量相关。甲基丙二酸水平与情景记忆和知觉速度较差相关，半胱氨酸和 2-甲基柠檬酸与情景和语义记忆较差相关。同型半胱氨酸浓度与总脑容量减少相关。同型半胱氨酸与整体认知的影响在调整白质体积或脑梗死后发生了变化，且不再具有统计学意义。甲基丙二酸与整体认知的影响在调整总脑容量后发生了变化，且不再显著。
甲基丙二酸是 B12 缺乏的特定标志物，可能通过减少总脑容量来影响认知，而同型半胱氨酸（与维生素 B12 缺乏无关）对认知表现的影响可能通过增加白质高信号和脑梗死来介导。维生素 B12 状态可能通过多种机制影响大脑。
