VITAMIN K AND BONE TURNOVER IN POSTMENOPAUSAL WOMEN

越来越多的数据表明，维生素K（K）不足可能会导致骨质疏松症的发展，通过引起增加骨转换。 然而，目前可用的数据不允许得出明确的结论，关于在骨代谢中的作用K。 许多证据表明，K在骨骼健康中的作用是利用血清低羧化骨钙素（ucOC）作为K状态的敏感指标。 当使用ucOC升高来定义K不足时，不足是非常常见的。 然而，这种“营养不足”是否与骨骼相关，或者ucOC浓度升高是否只是普遍营养不足的替代品，尚不清楚。为了阐明钾缺乏在骨骼健康中的作用，我们提出了一项为期14个月的前瞻性、随机、双盲、安慰剂对照试验，在226名绝经后妇女中补充K1。 我们假设，K1补充剂降低骨骼周转。 为了检验这一假设，我们将使用可使血清ucOC最大程度降低的K1剂量（1000 mcg/天）。 我们的具体目标是通过测量血清骨钙素、骨特异性碱性磷酸酶和I型胶原的N端肽以及尿吡啶啉和脱氧吡啶啉来评估骨骼转换。如果钾不足导致高骨转换，这是低骨量和骨质疏松性骨折的已知风险因素，则应增加推荐的钾摄入量，并将K1补充剂作为标准预防性医疗保健的一部分。

Accumulating data suggest that vitamin K (K) insufficiency may contribute to osteoporosis development by causing by causing increased bone turnover. However, currently available data do not permit definitive conclusions to be drawn regarding a role of K in bone metabolism. Much of the evidence implicating K in bone health utilizes measurement of serum undercarboxylated osteocalcin (ucOC) as a sensitive indicator of K status. When ucOC elevation is used to define K inadequacy, insufficiency is extremely common. However, whether this "insufficiency has skeletal relevance, or if elevated ucOC concentration is simply a surrogate for generalized inadequate nutrition, is unknown. To clarify the role of K insufficiency in skeletal health, we propose a 14 month, prospective, randomized, double-blind, placebo controlled trial of K1 supplementation in 226 postmenopausal women. We hypothesize that K1 supplementation reduces skeletal turnover. To test this hypothesis we will use a K1 dose (1000 mcg/day) that produces maximal reduction in serum ucOC. Our specific objective is to assess skeletal turnover by measuring serum osteocalcin, bone specific alkaline phosphatase, and N-telopeptides of type l collagen, as well as urinary pyridinoline and deoxypyridinoline. If K insufficiency causes high bone turnover, a known risk factor for low bone mass and osteoporotic fracture, the recommended K intake should be increased and K1 supplementation become part of standard preventative medical care.