Vitamin K and Bone in Children with Cerebral Palsy

描述（由申请人提供）：脑瘫（CP）是一种脑部疾病，可严重损害运动和姿势。中度至重度CP的主要继发性并发症是骨骼发育的严重损害和股骨骨折的高发生率。有一个因素与骨折密切相关，但尚未对CP儿童进行评估，那就是维生素K水平。维生素K是骨钙素羧化所必需的。骨钙素羧化不足与骨骼矿化不良有关。有趣的是，维生素K的摄入量并不总是与骨矿物质密度（aBMD）相关，aBMD是骨骼脆弱性的主要标志，但它与骨折有关。这种不一致表明维生素K与aBMD没有捕捉到的骨骼特征联系更紧密。据推测，羧化骨钙素水平与骨小梁微结构和骨几何结构有关。我们的长期目标是制定策略，最大限度地促进骨的生长和发育，减少CP儿童骨折的发生率。本研究的具体目的是：1)确定中度至重度CP儿童血清中羧基化骨钙素水平是否高于非CP儿童；2)确定有无CP患儿的骨钙素羧化水平是否与小梁微结构、几何结构和股骨强度呈负相关；3)确定羧化骨钙素是否与患有和不患有CP的儿童的aBMD和股骨骨矿物质含量呈负相关。为了实现我们的目标，我们将研究7至11岁患有中度至重度CP的青春期前儿童和没有CP的儿童。如果CP患儿的低羧化骨钙素水平升高，且与骨小梁微结构、几何结构和骨强度呈负相关，则表明维生素K可能在CP患儿或其他身体残疾儿童的骨折预防中发挥重要作用。

DESCRIPTION (provided by applicant): Cerebral palsy (CP) is a brain disorder that can seriously impair movement and posture. A major secondary complication of moderate to severe CP is a substantial compromise of bone development and a high incidence of fracture in the femur. One factor that is closely tied to fracture but has not been evaluated in children with CP is vitamin K status. Vitamin K is necessary for the carboxylation of osteocalcin. Undercarboxylation of osteocalcin is associated with poor mineralization of the skeleton. Interestingly, vitamin K intake is not consistently associated with areal bone mineral density (aBMD), the primary marker of skeletal fragility, but it is associated with fracture. This discordance suggests vitamin K is more closely tied to features of the skeleton not captured by aBMD. It has been inferred that the level of carboxylated osteocalcin is associated with the trabecular microarchitecture and geometric structure of bone. Our long- term goal is to develop strategies that maximize growth and development of bone and reduce the incidence of fracture in children with CP. The specific aims of this study are: 1) to determine if children with moderate to severe CP have a higher level of undercarboxylated osteocalcin in the serum than children without CP;2) to determine if undercarboxylated osteocalcin is inversely related to the status of trabecular microarchitecture, geometric structure and strength of the femur in children with and without CP; and 3) to determine if undercarboxylated osteocalcin is inversely related to aBMD and bone mineral content in the femur in children with and without CP. To address our aims, 7 to 11 year-old prepubertal children with moderate to severe CP and children without CP will be studied. If the level of undercarboxylated osteocalcin is elevated in children with CP and if it is inversely related to trabecular microarchitecture, geometric structure and strength of bone, it would suggest that vitamin K may play an important role in fracture prevention in children with CP or other physical disabilities.