Highlights • The BEST-D (Biochemical Efficacy and Safety Trial of vitamin D) trial will compare the biochemical and other effects of daily dietary supplementation with 100 μg or 50 μg vitamin D3 or placebo, when administered for 12 months, in 305 ambulant community-dwelling older people living in Oxfordshire, England.• The primary analyses will compare 12-month mean plasma concentrations of 25(OH)D as well as the proportion of participants with a 12-month concentration >90 nmol/L between participants allocated 100 μg and participants allocated 50 μg daily. Secondary analyses will compare the two active doses (both separately and when combined) with placebo.• Additional end-points include biochemical assessments of safety, blood pressure, arterial stiffness, falls, fractures, heel and wrist bone density, grip strength and physical performance and echocardiographic assessments of cardiac function in a random sample of participants.• The results of this trial will help determine the optimum dose of vitamin D to test in a larger trial investigating whether vitamin D supplementation can reduce the risk of fractures, cardiovascular disease or cancer.

中文翻译：

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估计老年人疾病预防中维生素 D 的最佳剂量：BEST-D 试验的基本原理、设计和基线特征

亮点 • BEST-D（维生素 D 的生化功效和安全性试验）试验将比较每日膳食补充剂与 100 μg 或 50 μg 维生素 D3 或安慰剂在 305 名可移动社区中给药 12 个月时的生化和其他效果-居住在英国牛津郡的老年人。• 主要分析将比较 25(OH)D 的 12 个月平均血浆浓度以及分配 100 μg 的参与者之间 12 个月浓度 >90 nmol/L 的参与者比例参与者每天分配 50 微克。次要分析将比较两种活性剂量（单独和组合时）与安慰剂。• 其他终点包括安全性、血压、动脉僵硬、跌倒、骨折、足跟和腕骨密度的生化评估，