School of Agriculture, Food, and Rural Development, Newcastle University, Newcastle-upon-Tyne, UK; Newcastle University Institute for Ageing, Newcastle-upon-Tyne, UK; Human Nutrition Research Centre, Newcastle University, Newcastle-upon-Tyne, UK; Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
Newcastle University Institute for Ageing, Newcastle-upon-Tyne, UK; Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, UK; NIHR Newcastle Biomedical Research Centre in Ageing and Chronic Disease, Newcastle University and Newcastle-upon-Tyne NHS Foundation Trust, Newcastle-upon-Tyne, UK.
J Am Med Dir Assoc. 2017 Sep 1;18(9):806.e19-806.e27. doi: 10.1016/j.jamda.2017.05.008. Epub 2017 Jun 21.
Although the biological rationale for the association between folate, vitamin B12, and homocysteine with cognitive function seems plausible, conflicting results have been reported. This study aimed to determine the associations between 1-carbon (1-C) metabolism biomarkers (folate, vitamin B12, and homocysteine), and cognitive impairment at baseline and the rate of cognitive decline over 5 years in the very old.
The Newcastle 85+ Study was a prospective longitudinal study of people 85 years old and followed over 5 years in Northeast England.
Community-dwelling and institutionalized.
The analytical sample included 765 very old participants with 1-C metabolism biomarkers and cognitive measures.
Global cognition was measured by the Standardized Mini-Mental State Examination (SMMSE) at baseline, and at 3 and 5 years of follow-up and, attention-specific cognition with the Cognitive Drug Research (CDR) System at baseline, and at 1.5 and 3.0 years of follow-up. Baseline red blood cell folate (RBC folate), plasma vitamin B12, and total homocysteine (tHcy) concentrations were determined by immunoassay. Linear mixed models were used to estimate the associations between quartiles of 1-C metabolism biomarkers and cognition over 3 (CDR) and 5 years (SMMSE).
Compared with participants in the lowest quartile of RBC folate concentrations (<612 nmol/L), those in the highest quartile of RBC folate concentrations (>1280 nmol/L) had 1 more point on the SMMSE at baseline (β = +1.02, SE = 0.43, P = .02). Those in quartile 4 of tHcy (>21.4 μmol/L) had 1 point less in the SMMSE at baseline than those in the lowest quartile (<13.5 μmol/L) (β = -1.05, SE = 0.46, P = .02). Plasma vitamin B12 was not predictive of global or attention-specific cognition at baseline and at follow-up. None of the 1-C metabolism biomarkers except tHcy was associated with the rate of decline in attention scores over 3 years.
RBC folate and tHcy, but not plasma vitamin B12, were associated with better global cognition in the very old at baseline but were not predictive of rate of decline over 5 years.
尽管叶酸、维生素 B12 和同型半胱氨酸与认知功能之间的关联具有生物学合理性，但已有研究结果相互矛盾。本研究旨在确定在非常高龄人群中，1 碳（1-C）代谢生物标志物（叶酸、维生素 B12 和同型半胱氨酸）与基线时的认知障碍以及 5 年内认知能力下降速度之间的相关性。
纽卡斯尔 85+研究是一项针对英格兰东北部地区 85 岁及以上人群的前瞻性纵向研究。
社区居住和机构居住。
分析样本包括 765 名非常高龄参与者，他们具有 1-C 代谢生物标志物和认知测量值。
基线时使用标准化简易精神状态检查（SMMSE）测量整体认知，随访 3 年和 5 年时进行测量，使用认知药物研究（CDR）系统测量注意力特异性认知，基线时进行测量，随访 1.5 年和 3.0 年时进行测量。通过免疫测定法测定红细胞叶酸（RBC 叶酸）、血浆维生素 B12 和总同型半胱氨酸（tHcy）浓度。使用线性混合模型来估计在 3 年（CDR）和 5 年（SMMSE）时，1-C 代谢生物标志物的四分位数与认知之间的相关性。
与 RBC 叶酸浓度最低四分位数（<612nmol/L）的参与者相比，RBC 叶酸浓度最高四分位数（>1280nmol/L）的参与者基线时 SMMSE 得分高 1 分（β=+1.02，SE=0.43，P=0.02）。与 tHcy 最低四分位数（<13.5μmol/L）的参与者相比，tHcy 最高四分位数（>21.4μmol/L）的参与者基线时 SMMSE 得分低 1 分（β=-1.05，SE=0.46，P=0.02）。血浆维生素 B12 与基线时和随访时的整体认知或注意力特异性认知均无相关性。除 tHcy 外，1-C 代谢生物标志物中没有任何一种与 3 年内注意力评分的下降速度相关。
RBC 叶酸和 tHcy，而不是血浆维生素 B12，与非常高龄人群的基线时整体认知较好相关，但不能预测 5 年内的下降速度。
