TY - JOUR
T1 - Vitamin K status of healthy Japanese women
T2 - Age-related vitamin K requirement for γ-carboxylation of osteocalcin
AU - Tsugawa, Naoko
AU - Shiraki, Masataka
AU - Suhara, Yoshitomo
AU - Kamao, Maya
AU - Tanaka, Kiyoshi
AU - Okano, Toshio
PY - 2006/2/1
Y1 - 2006/2/1
N2 - Background: Vitamin K deficiency is associated with low bone mineral density and increased risk of bone fracture. Phylloquinone (K1) and menaquinone 4 (MK-4) and 7 (MK-7) are generally observed in human plasma; however, data are limited on their circulating concentrations and their associations with bone metabolism or with γ-carboxylation of the osteocalcin molecule. Objectives: The objectives were to measure the circulating concentrations of K1, MK-4, and MK-7 in women and to ascertain whether each form of vitamin K is significantly associated with bone metabolism. Design: Plasma concentrations of K1, MK-4, MK-7, undercarboxylated osteocalcin (ucOC; measured by using the new electrochemiluminescence immunoassay), intact osteocalcin (iOC), calcium, and phosphorus; bone-derived alkaline phosphatase activity; and concentrations of urinary creatinine, N-terminal telopeptide, and deoxypyridinoline were measured in healthy women (n = 396). Results: On average, MK-7 and MK-4 were the highest and lowest, respectively, of the 3 vitamers in all age groups. K1 and MK-7 correlated inversely with ucOC, but associations between nutritional basal concentration of MK-4 and ucOC were not observed. Multiple regression analysis indicated that not only K1 and MK-7 concentrations but also age were independently correlated with ucOC concentration and the ratio of ucOC to iOC. The plasma K1 or MK-7 concentration required to minimize the ucOC concentration was highest in the group aged ≥70 y, and it decreased progressively for each of the younger age groups. Conclusions: The definite role of ucOC remains unclear. However, if submaximal γ-carboxylation is related to the prevention of fracture or bone mineral loss, circulating vitamin K concentrations in elderly people should be kept higher than those in young people.
AB - Background: Vitamin K deficiency is associated with low bone mineral density and increased risk of bone fracture. Phylloquinone (K1) and menaquinone 4 (MK-4) and 7 (MK-7) are generally observed in human plasma; however, data are limited on their circulating concentrations and their associations with bone metabolism or with γ-carboxylation of the osteocalcin molecule. Objectives: The objectives were to measure the circulating concentrations of K1, MK-4, and MK-7 in women and to ascertain whether each form of vitamin K is significantly associated with bone metabolism. Design: Plasma concentrations of K1, MK-4, MK-7, undercarboxylated osteocalcin (ucOC; measured by using the new electrochemiluminescence immunoassay), intact osteocalcin (iOC), calcium, and phosphorus; bone-derived alkaline phosphatase activity; and concentrations of urinary creatinine, N-terminal telopeptide, and deoxypyridinoline were measured in healthy women (n = 396). Results: On average, MK-7 and MK-4 were the highest and lowest, respectively, of the 3 vitamers in all age groups. K1 and MK-7 correlated inversely with ucOC, but associations between nutritional basal concentration of MK-4 and ucOC were not observed. Multiple regression analysis indicated that not only K1 and MK-7 concentrations but also age were independently correlated with ucOC concentration and the ratio of ucOC to iOC. The plasma K1 or MK-7 concentration required to minimize the ucOC concentration was highest in the group aged ≥70 y, and it decreased progressively for each of the younger age groups. Conclusions: The definite role of ucOC remains unclear. However, if submaximal γ-carboxylation is related to the prevention of fracture or bone mineral loss, circulating vitamin K concentrations in elderly people should be kept higher than those in young people.
KW - Bone turnover makers
KW - Healthy elderly women
KW - Menaquinone 4
KW - Menaquinone 7
KW - Osteocalcin
KW - Phylloquinone
KW - Plasma concentrations
KW - Vitamin K
UR - http://www.scopus.com/inward/record.url?scp=33644856016&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33644856016&partnerID=8YFLogxK
U2 - 10.1093/ajcn/83.2.380
DO - 10.1093/ajcn/83.2.380
M3 - Article
C2 - 16469998
AN - SCOPUS:33644856016
VL - 83
SP - 380
EP - 386
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
SN - 0002-9165
IS - 2
ER -