Impaired gamma carboxylation of osteocalcin in elderly women with type II diabetes mellitus: relationship between increase in undercarboxylated osteocalcin levels and low bone mineral density.
We conducted a cross-sectional examination of the role of serum vitamin K levels as they relate to bone metabolism in elderly women with type II diabetes mellitus (DM). Eighty-five elderly women with type II DM were enrolled. Three fractions of vitamin K, phylloquinone (PK), menaquinone 4 (menatetrenone; MK 4), and menaquinone 7 (MK 7), along with undercarboxylated osteocalcin (UcOC), intact osteocalcin (IOC), urinary deoxypyridinoline (udpd), urinary type I collagen N-telopeptide (NTx), and intact parathyroid hormone (IPTH) were measured. Bone mineral density was measured in the lumbar spine (LSBMD) by dual-energy X-ray absorptiometry (DXA), and T scores or Z scores were calculated. The patients were divided into two groups by T score, under -2.5 (osteoporotic group) and over -2.5 (non-osteoporotic group). UcOC levels in osteoporotics patients were significantly higher than those in the non-osteoporotic group (3.09 +/- 3.94 vs 1.82 +/- 1.76 ng/ml, P = 0.02). The correlation between Z score and logarithmic UcOC/IOC levels in type II DM showed a negative trend ( P = 0.07) and a significantly and negatively association with logarithmic NTx ( r = -0.38; P = 0.001). In osteoporotic DM, the UcOC/IOC ratio was significantly correlated with the Z score ( r = -0.61; P << 0.05). Furthermore, logarithmic UcOC/IOC showed a negative correlation with logarithmic MK 7 ( r = -0.50; P = 0.001). In conclusion, the reduction in LSBMD in elderly women with type II DM may be associated, in part, with a defect in Gamma-glutamylcarboxylation by vitamin K.
Horiuchi
Toshiyuki
T
Department of Endocrinology, Tokyo Metropolitan Geriatric Medical Center, 35-2 Sakae-cho, Itabashi-ku, Tokyo 1173-0015, Japan. thori@tmgh.metro.tokyo.jp
Kazama
Hirohito
H
Araki
Atsushi
A
Inoue
Junichiro
J
Hosoi
Takayuki
T
Onouchi
Tsuneko
T
Mizuno
Shouichi
S
Ito
Hideki
H
Orimo
Hajime
H
D000368:Aged; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000378:metabolism; D015519:Bone Density / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D015675:Osteocalcin / Q000097:blood / Q000378:metabolism*; D014812:Vitamin K / Q000032:analysis; D024482:Vitamin K 2 / Q000031:analogs & derivatives* / Q000032:analysis
D015415:Biomarkers; D015675:Osteocalcin; D024482:Vitamin K 2; D014812:Vitamin K; C030814:menatetrenone; C062629:menaquinone 7