Bone Is More Susceptible to Vitamin K Deficiency than Liver in the Institutionalized Elderly

居住機構老人骨骼比肝臟易受維生素K缺乏影響

Akiko Kuwabara ； Minori Fujii ； Nobuko Kawai ； Kunihiko Tozawa ； Shoko Kido ； Kiyoshi Tanaka

《Asia Pacific Journal of Clinical Nutrition》 20卷1期 (2011/03) Pp. 50-55

https://doi.org/10.6133/apjcn.2011.20.1.08

摘要

日本2010年發佈的膳食營養素參考攝取量（DRI）中，維生素K的足夠攝取量是根據凝血因子的γ-羧化作用而訂定的。近來，維生素K也被視為預防骨折不可或缺的角色。本研究在於比較肝和骨骼對維生素K缺乏的敏感性。評估37位居住機構的老人之維生素K狀況－測量血清PIVKA-II（因維生素K缺乏所產生的蛋白質）和ucOC（未羧化的骨鈣素）濃度，兩者分別為肝和骨骼在維生素K缺乏時的敏感指標。受試者血清PIVKA-II和ucOC濃度分別為20.2±8.9 mAU/mL（臨界值28 mAU/mL）和4.7±3.0 ng/mL（臨界值4.5 ng/mL）。維生素K攝取量中位數約為200 μg/day，超過了日本目前所建議的足夠攝取量3倍。維生素K攝取量與血清PIVKA-II和ucOC/OC濃度顯著相關，但與血清ucOC濃度無相關。雖然血清ucOC濃度是體內維生素K狀況很好的指標，但複迴歸分析顯示骨骼轉換標記增加，也會影響血清ucOC濃度。所有的受試者維生素K攝取量皆超過足夠攝取量。然而，分別有14%和43%受試者的血清PIVKA-II和ucOC濃度超過臨界值。本研究結果建議，對於住在機構的老人，為維持骨骼健康，維生素K攝取量應超過目前建議的足夠攝取量。

關鍵字

維生素K ； 足夠攝取量 ； γ-羧化作用 ； 未羧化骨鈣素 ； PIVKA-II

並列摘要

In Japan, γ-carboxylation of blood coagulation factors is the basis for determining adequate intake (AI) for vitamin K in Dietary Reference Intakes (DRIs) issued in 2010. Recently, vitamin K is also known to be essential for preventing fracture. In this study, relative susceptibility of liver and bone to vitamin K deficiency was studied. Thirty-seven elderly institutionalized subjects were evaluated for vitamin K status by measuring serum PIVKA (protein induced by vitamin K absence)-II and ucOC (undercarboxylated osteocalcin) levels, as sensitive markers for hepatic and skeletal vitamin K deficiency, respectively. Serum PIVKA-II and ucOC levels, with their cut-off values in the parentheses, were 20.2±8.9 mAUmL (28 mAU/mL) and 4.7±3.0 ng/mL (4.5 ng/mL), respectively. Median vitamin K intake was approximately 200 μg/day, which is more than 3 times higher than the current Japanese AI. Vitamin K intake was significantly correlated with serum PIVKA-II and ucOC/OC levels, but not with serum ucOC level. Although serum ucOC level is generally a good indicator for vitamin K status, multiple regression analysis revealed that elevated bone turnover marker significantly contributed to serum ucOC level. All subjects had vitamin K intake exceeding AI for vitamin K. Nevertheless, serum PIVKA-II and ucOC concentrations exceeded the cut-off value in 14% and 43% of subjects, respectively. The present findings suggest that vitamin K intake greater than the current AI is required for the skeletal health in the institutionalized elderly.

並列關鍵字

vitamin K ； adequate intake ； γ-carboxylation ； ucOC ； PIVKA-II