Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine, Queen Mary University of London, London, UK.
Am J Med. 2010 Jun;123(6):522-527.e2. doi: 10.1016/j.amjmed.2010.01.017.
We aimed to quantify the effect of folic acid supplementation on the prevention of cognitive decline.
We conducted a meta-analysis of 9 placebo-controlled randomized trials (2835 participants, median duration 6 months) of folic acid, with or without other B vitamins, on cognitive function. Standardized mean differences in cognitive function test scores were calculated between folic acid and placebo-treated groups.
The standardized mean difference in cognitive function test scores was 0.01 (95% confidence interval [95% CI], -0.08 to 0.10), or an increase of 1% (95% CI, -8% to 10%) of 1 standard deviation. The results were similar within each of the 4 categories of cognitive function (memory, speed, language, and executive function); standardized mean differences were 0.01 (95% CI, -0.08 to 0.09), -0.01 (95% CI, -0.10 to 0.13), -0.05 (95% CI, -0.15 to 0.04), and 0.03 (95% CI, -0.13 to 0.19), respectively.
Randomized trials show no effect of folic acid, with or without other B vitamins, on cognitive function within 3 years of the start of treatment. Trials of longer duration, recording the incidence of dementia, as well as cognitive decline, are needed.
我们旨在量化叶酸补充对预防认知能力下降的影响。
我们对 9 项安慰剂对照随机试验（2835 名参与者，中位随访时间为 6 个月）进行了荟萃分析，这些试验评估了叶酸（联合或不联合其他 B 族维生素）对认知功能的影响。计算叶酸组和安慰剂组认知功能测试评分的标准化均数差值。
认知功能测试评分的标准化均数差值为 0.01（95%置信区间[95%CI]，-0.08 至 0.10），即每增加 1 个标准差，增加 1%（95%CI，-8%至 10%）。在认知功能的 4 个分类（记忆、速度、语言和执行功能）中，结果均相似；标准化均数差值分别为 0.01（95%CI，-0.08 至 0.09）、-0.01（95%CI，-0.10 至 0.13）、-0.05（95%CI，-0.15 至 0.04）和 0.03（95%CI，-0.13 至 0.19）。
随机试验显示，在治疗开始后 3 年内，叶酸（联合或不联合其他 B 族维生素）对认知功能无影响。需要进行更长时间的试验，以记录痴呆症的发病率以及认知能力下降情况。
