Ann Intern Med. 2013 Dec 17;159(12):806-14. doi: 10.7326/0003-4819-159-12-201312170-00006.
Despite widespread use of multivitamin supplements, their effect on cognitive health-a critical issue with aging-remains inconclusive. To date, no long-term clinical trials have studied multivitamin use and cognitive decline in older persons.
To evaluate whether long-term multivitamin supplementation affects cognitive health in later life.
Randomized, double-blind, placebo-controlled trial of a multivitamin from 1997 to 1 June 2011. The cognitive function substudy began in 1998. Up to 4 repeated cognitive assessments by telephone interview were completed over 12 years. (ClinicalTrials.gov: NCT00270647) SETTING: The Physicians' Health Study II.
5947 male physicians aged 65 years or older.
Daily multivitamin or placebo.
A global composite score averaging 5 tests of global cognition, verbal memory, and category fluency. The secondary end point was a verbal memory score combining 4 tests of verbal memory, which is a strong predictor of Alzheimer disease.
No difference was found in mean cognitive change over time between the multivitamin and placebo groups or in the mean level of cognition at any of the 4 assessments. Specifically, for the global composite score, the mean difference in cognitive change over follow-up was -0.01 SU (95% CI, -0.04 to 0.02 SU) when treatment was compared with placebo. Similarly, cognitive performance did not differ between the multivitamin and placebo groups on the secondary outcome, verbal memory (mean difference in cognitive change over follow-up, -0.005 SU [CI, -0.04 to 0.03 SU]).
Doses of vitamins may be too low or the population may be too well-nourished to benefit from a multivitamin.
In male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits.
National Institutes of Health, BASF, Pfizer, and DSM Nutritional Products.
尽管多种维生素补充剂被广泛使用，但它们对认知健康的影响——这是老龄化的一个关键问题——仍不确定。迄今为止，尚无长期临床试验研究老年人使用多种维生素与认知能力下降之间的关系。
评估长期使用多种维生素是否会影响老年人的认知健康。
1997 年至 2011 年 6 月 1 日进行的一项随机、双盲、安慰剂对照的多种维生素试验。认知功能子研究于 1998 年开始。在 12 年期间通过电话访谈完成了多达 4 次重复认知评估。（ClinicalTrials.gov：NCT00270647）
医师健康研究 II。
5947 名年龄在 65 岁或以上的男性医生。
每日服用多种维生素或安慰剂。
全球认知、言语记忆和类别流畅性 5 项测试的综合评分。次要终点是结合言语记忆的 4 项测试的言语记忆评分，这是阿尔茨海默病的有力预测指标。
在多种维生素组和安慰剂组之间，随时间推移的认知变化平均值或在 4 次评估中的任何一次认知水平的平均值均未发现差异。具体而言，对于全球综合评分，与安慰剂相比，随访期间认知变化的平均差异为-0.01 SU（95%CI，-0.04 至 0.02 SU）。同样，多种维生素组和安慰剂组在次要结局（言语记忆）上的认知表现也没有差异（随访期间认知变化的平均差异，-0.005 SU[CI，-0.04 至 0.03 SU]）。
维生素的剂量可能太低，或者人群的营养状况可能太好，无法从多种维生素中受益。
在年龄在 65 岁或以上的男性医生中，长期使用每日多种维生素并不能带来认知益处。
美国国立卫生研究院、巴斯夫、辉瑞和 DSM 营养产品。
