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

• Published in: Journal of bone and mineral metabolism Vol. 22; no. 3; pp. 236 - 240
• Main Authors: HORIUCHI, Toshiyuki, KAZAMA, Hirohito, ARAKI, Atsushi, INOUE, Junichiro, HOSOI, Takayuki, ONOUCHI, Tsuneko, MIZUNO, Shouichi, ITO, Hideki, ORIMO, Hajime
• Format: Journal Article
• Language: English
• Published: Tokyo Springer 01-05-2004; Springer Nature B.V
• Subjects: Aged; Aging; Biological and medical sciences; Biomarkers - analysis; Biomarkers - blood; Biomarkers - metabolism; Bone density; Bone Density - physiology; Bones; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - metabolism; Diabetes. Impaired glucose tolerance; Diseases of the osteoarticular system; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Humans; Medical sciences; Older people; Osteocalcin - blood; Osteocalcin - metabolism; Osteoporosis; Vitamin K - analysis; Vitamin K 2 - analogs & derivatives; Vitamin K 2 - analysis; Endocrinopathy; Human; Type 2 diabetes; Osteocalcin; Low; Rheumatology; Carboxylation; Female; Increase; Bone mineral density; Woman; Elderly
• ISSN: 0914-8779; 1435-5604
• DOI: 10.1007/s00774-003-0473-z

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.