Clarke Robert, Bennett Derrick, Parish Sarah, Lewington Sarah, Skeaff Murray, Eussen Simone J P M, Lewerin Catharina, Stott David J, Armitage Jane, Hankey Graeme J, Lonn Eva, Spence J David, Galan Pilar, de Groot Lisette C, Halsey Jim, Dangour Alan D, Collins Rory, Grodstein Francine
From the Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, United Kingdom (R Clarke, DB, SP, SL, JA, JH, and R Collins); the Department of Human Nutrition, University of Otago, Dunedin, New Zealand (MS); the Section for Pharmacology and Department of Public Health and Primary Care, University of Bergen, Bergen, Norway (SJPME); the Department of Epidemiology, School for Public Health and Primary Care, CAPHRI, Maastricht University Medical Centre, Maastricht, Netherlands (SJPME); the Section of Hematology and Coagulation, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden (CL); the Division of Cardiovascular and Medical Science, University of Glasgow, Glasgow, United Kingdom (DJS); the School of Medicine and Pharmacology, The University of Western Australia, Perth, Australia (GJH); the Population Health Research Institute and Department of Medicine, McMaster University, Hamilton, Canada (EL); the Department of Neurology, Western University, London, Canada (JDS); Unité de Recherche en Epidémiologie Nutritonnelle (UREN), Sorbonne-Paris-Cité, UMR Inserm U557, France (PG); Inra U1125, Paris, France (PG); Cnam, Paris, France (PG); Université Paris 13, CRNH IdF, Bobigny, France (PG); the Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, Netherlands (LCdG); the Department of Nutrition and Public Health Intervention Research, London School of Hygiene and Tropical Medicine, London, United Kingdom (ADD); and the Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA (FG).
Am J Clin Nutr. 2014 Aug;100(2):657-66. doi: 10.3945/ajcn.113.076349. Epub 2014 Jun 25.
Elevated plasma homocysteine is a risk factor for Alzheimer disease, but the relevance of homocysteine lowering to slow the rate of cognitive aging is uncertain.
The aim was to assess the effects of treatment with B vitamins compared with placebo, when administered for several years, on composite domains of cognitive function, global cognitive function, and cognitive aging.
A meta-analysis was conducted by using data combined from 11 large trials in 22,000 participants. Domain-based z scores (for memory, speed, and executive function and a domain-composite score for global cognitive function) were available before and after treatment (mean duration: 2.3 y) in the 4 cognitive-domain trials (1340 individuals); Mini-Mental State Examination (MMSE)-type tests were available at the end of treatment (mean duration: 5 y) in the 7 global cognition trials (20,431 individuals).
The domain-composite and MMSE-type global cognitive function z scores both decreased with age (mean ± SE: -0.054 ± 0.004 and -0.036 ± 0.001/y, respectively). Allocation to B vitamins lowered homocysteine concentrations by 28% in the cognitive-domain trials but had no significant effects on the z score differences from baseline for individual domains or for global cognitive function (z score difference: 0.00; 95% CI: -0.05, 0.06). Likewise, allocation to B vitamins lowered homocysteine by 26% in the global cognition trials but also had no significant effect on end-treatment MMSE-type global cognitive function (z score difference: -0.01; 95% CI: -0.03, 0.02). Overall, the effect of a 25% reduction in homocysteine equated to 0.02 y (95% CI: -0.10, 0.13 y) of cognitive aging per year and excluded reductions of >1 mo per year of treatment.
Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging.
血浆同型半胱氨酸水平升高是阿尔茨海默病的一个危险因素，但降低同型半胱氨酸水平对减缓认知衰老速度的相关性尚不确定。
旨在评估与安慰剂相比，连续数年服用B族维生素对认知功能综合领域、整体认知功能和认知衰老的影响。
通过合并来自11项大型试验（共22000名参与者）的数据进行荟萃分析。在4项认知领域试验（1340人）中，治疗前后（平均持续时间：2.3年）可获得基于领域的z分数（用于记忆、速度和执行功能以及整体认知功能的领域综合分数）；在7项整体认知试验（20431人）中，治疗结束时（平均持续时间：5年）可获得简易精神状态检查表（MMSE）类型的测试结果。
领域综合分数和MMSE类型的整体认知功能z分数均随年龄下降（平均值±标准误：分别为-0.054±0.004和-0.036±0.001/年）。在认知领域试验中，分配到B族维生素组可使同型半胱氨酸浓度降低28%，但对各个领域或整体认知功能与基线相比的z分数差异无显著影响（z分数差异：0.00；95%置信区间：-0.05，0.06）。同样，在整体认知试验中，分配到B族维生素组可使同型半胱氨酸降低26%，但对治疗结束时MMSE类型的整体认知功能也无显著影响（z分数差异：-0.01；95%置信区间：-0.03，0.02）。总体而言，同型半胱氨酸降低25%的效果相当于每年认知衰老0.02年（95%置信区间：-0.10，0.13年），且排除了每年治疗减少超过1个月的情况。
使用B族维生素降低同型半胱氨酸对个体认知领域、整体认知功能或认知衰老无显著影响。
