Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada.
McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada; Departments of Medicine, Community Health Sciences, and Oncology, University of Calgary, Calgary, Canada.
Contemp Clin Trials. 2018 Apr;67:68-73. doi: 10.1016/j.cct.2018.02.009. Epub 2018 Feb 20.
The optimum dose of vitamin D and corresponding serum 25-hydroxyvitamin D (25OHD) concentration for bone health is still debated and some health practitioners are recommending doses well above the Canada/USA recommended Dietary Reference Intake (DRI). We designed a three-year randomized double-blind clinical trial investigating whether there are dose-dependent effects of vitamin D supplementation above the Dietary Reference Intake (DRI) on bone health. The primary aims of this study are to assess, whether supplementation of vitamin D increases 1) volumetric bone mineral density measured by high-resolution peripheral quantitative computed tomography (HR-pQCT); 2) bone strength assessed by finite element analysis, and 3) areal bone mineral density by dual X-ray absorptiometry (DXA). Secondary aims are to understand whether vitamin D supplementation improves parameters of bone microarchitecture, balance, physical function and quality of life. Participants are men and women aged 55-70 years, with women at least 5-years post-menopause. The intervention is daily vitamin D supplementation doses of 400, 4000 or 10,000 IU. Participants not achieving adequate dietary calcium intake are provided with calcium supplementation, up to a maximum supplemental dose of 600 mg elemental calcium per day. Results from this three-year study will provide evidence whether daily vitamin D supplementation with adequate calcium intake can affect bone density, bone microarchitecture and bone strength in men and women. Furthermore, the safety of high dose daily vitamin D supplementation will be explored.
关于维生素 D 的最佳剂量和相应的血清 25-羟维生素 D（25OHD）浓度以促进骨骼健康仍存在争议，一些医疗从业者建议的剂量远远超过加拿大/美国推荐的膳食参考摄入量（DRI）。我们设计了一项为期三年的随机双盲临床试验，旨在研究维生素 D 补充剂量是否存在高于膳食参考摄入量（DRI）的剂量依赖性作用对骨骼健康的影响。该研究的主要目的是评估补充维生素 D 是否可以：1）通过高分辨率外周定量计算机断层扫描（HR-pQCT）增加体积骨矿物质密度；2）通过有限元分析评估骨强度；3）通过双能 X 线吸收法（DXA）评估面积骨矿物质密度。次要目标是了解维生素 D 补充是否可以改善骨微结构、平衡、身体机能和生活质量的参数。研究对象为年龄在 55-70 岁之间的男性和女性，其中女性至少绝经 5 年。干预措施为每天补充 400、4000 或 10000 IU 的维生素 D。对于未达到足够膳食钙摄入量的参与者，将提供钙补充剂，每天最高补充剂量为 600mg 元素钙。这项为期三年的研究结果将提供证据，证明在摄入足够钙的情况下，每天补充维生素 D 是否可以影响男性和女性的骨密度、骨微结构和骨强度。此外，还将探索高剂量每日维生素 D 补充的安全性。
