Epidemiological studies show mixed findings for serum vitamin B12 (B12) and both cognitive and regional volume outcomes. No studies to date have comprehensively examined, in non-supplemented individuals, serum B12 level associations with neurodegeneration, hypometabolism and cognition across the Alzheimerʼs disease (AD) spectrum. Serum B12 was assayed from the Alzheimerʼs Disease Neuroimaging Initiative (ADNI) and the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL). Voxel-wise analyses regressed B12 levels against regional grey matter (GM) volume and glucose metabolism (P < 0·05, family-wise corrected). For ADNI GM, there were thirty-nine cognitively normal (CN), seventy-three mild cognitive impairment (MCI) and thirty-one AD participants. For AIBL GM, there were 311 CN, fifty-nine MCI and thirty-one AD participants. Covariates were age, sex, baseline diagnosis, APOE4 status and BMI. In ADNI, higher B12 was negatively associated with GM in the right precuneus and bilateral frontal gyri. When diagnostic groups were examined separately, only participants with MCI, or above an established cut-off for cerebrospinal fluid (CSF) total tau showed such associations. In AIBL, higher B12 was associated with more GM in the right amygdala and right superior temporal pole, which largely seemed to be driven by CN participants that constituted most of the sample. Our results suggest that B12 may show different patterns of association based on clinical status and, for ADNI, AD CSF biomarkers. Accounting for these factors may clarify the relationship between B12 with neural outcomes in late-life.

中文翻译：

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血清维生素 B12 和相关的 5-甲基四氢叶酸-同型半胱氨酸甲基转移酶还原酶和 cubilin 基因型可预测阿尔茨海默病谱的神经结果

流行病学研究显示血清维生素 B 的混合结果12(乙12) 以及认知和区域容量结果。迄今为止，尚无研究全面检查未服用补充剂的个体的血清 B12与阿尔茨海默氏病 (AD) 谱系中的神经变性、代谢减退和认知水平相关。血清B12由阿尔茨海默氏病神经影像学倡议 (ADNI) 和澳大利亚衰老成像、生物标志物和生活方式旗舰研究 (AIBL) 进行了分析。体素分析回归 B12区域灰质 (GM) 体积和葡萄糖代谢水平 (P< 0·05，家庭方面更正）。对于 ADNI GM，有 39 名认知正常 (CN)、73 名轻度认知障碍 (MCI) 和 31 名 AD 参与者。对于 AIBL GM，有 311 名 CN、59 名 MCI 和 31 名 AD 参与者。协变量是年龄、性别、基线诊断、载脂蛋白E4状态和体重指数。在 ADNI 中，较高的 B12与右侧楔前叶和双侧额回的 GM 呈负相关。当单独检查诊断组时，只有患有 MCI 或高于既定的脑脊液 (CSF) 总 tau 截断值的参与者显示出这种关联。在 AIBL 中，更高的 B12与右侧杏仁核和右侧颞上极中更多的 GM 有关，这在很大程度上似乎是由构成大部分样本的 CN 参与者驱动的。我们的结果表明 B12可能会根据临床状态显示不同的关联模式，对于 ADNI，AD CSF 生物标志物。考虑到这些因素可能会澄清 B 之间的关系12与晚年的神经结果。