Optimizing vitamin D in the elderly

描述（由申请人提供）：维生素D缺乏症在缺乏维生素D补充的老年人中非常普遍。有限的可用数据显示，在接受目前推荐的800 IU/day维生素D的情况下，年老体弱的老年人几乎有25%的维生素D缺乏（25-OH D < 20 ng/mL），对维生素D补充的反应存在显著的个体差异。该建议是对生活在受控生活环境中的年老体口服维生素D3剂量的广泛使用进行探索性研究。我们将在一项随机盲法研究中确定总25-OH维生素D3和未结合的25-OH维生素D3与补充维生素D3的剂量反应关系，每日剂量分别为800（目前推荐用于老年人）、2000、4000 IU或50,000 IU/周。我们还将比较每种给药方案在达到25-OH维生素D水平bbb20 ng/mL （50 nmol/L）方面的疗效，并确定导致剂量反应关系个体间差异的协变量。在骨质疏松症患者中，将分析完整甲状旁腺激素未结合与总25-OH与骨吸收标志物（β - ctx）之间的关系。我们还将检查炎症细胞因子的反应。长期目标是开发估算D3剂量的算法，以达到老年人和体弱个体25-OH维生素D的目标剂量。

DESCRIPTION (provided by applicant): Vitamin D deficiency is highly prevalent in older people in the absence of vitamin D supplementation. The limited data available show marked inter-individual variability in response to vitamin D supplementation in very old, frail elderly wih almost 25% remaining vitamin D deficient (25-OH D < 20 ng/mL) when receiving the currently recommended 800 IU/day vitamin D. This proposal is for exploratory research on the use of a wide range of oral vitamin D3 doses in frail elderly living in controlled living environments. We will determine the dose response relationship of total and unbound 25- OH vitamin D3 to supplemental vitamin D3 at daily doses of 800 (currently recommended for the elderly), 2000, and 4000 IU or 50,000 IU/weekly in a randomized blinded investigation We will also compare the efficacy of each dosing regimen in achieving 25-OH vitamin D levels >20 ng/mL (50 nmol/L) and identify covariates that contribute to inter-individual variation in the dose response relationship. In patients with osteoporosis, relationships between unbound vs. total 25-OH on intact parathyroid hormone and a marker of bone resorption (beta-Ctx) will be analyzed. We will also examine responses of inflammatory cytokines. A long-term goal is to develop algorithms for estimation of D3 dosages to achieve target 25-OH vitamin D doses for very elderly and frail individuals. PUBLIC HEALTH RELEVANCE: Vitamin D deficiency is very common in the elderly but the dose required to normalize vitamin D levels has not been determined for very old or frail people. This proposal will evaluate responses to a wide range of daily oral vitamin D3 doses and a higher weekly dose of oral vitamin D3 in old, very old, frail, and nursing home patients to determine the best dose to correct vitamin D deficiency in the almost 2 million elderly Americans living in nursing homes. It will also explore what doses of vitamin D decrease inflammation and bone resorption.