抄録
Undercarboxylated osteocalcin (ucOC) is a marker of vitamin K deficiency, and an increased ucOC level is considered a predictor of hip fracture. In this study we evaluated the effect of anti-osteoporosis drugs and bone turn-over on the serum ucOC levels.
We measured serum ucOC levels in 115 patients with osteoporosis (average age 76.5 years). Forty patients had been taking vitamin D, 9 had been taking bisphosphonate, 12 had been taking bisphosphonate+vitamin D, and 10 had been taking vitamin D+vitamin K, each for at least 6 months. Forty-four patients had received no therapy for osteoporosis. Patients whose serum ucOC level was above the normal limit (4.5ng/ml), were prescribed additional vitamin K medication for 6 months.
The average serum ucOC level was 6.84±6.56ng/ml. The serum ucOC level exceeded the normal limit in 50.4% of the patients, but was low in patients who had taken vitamin K or bisphosphonate. The ucOC level tended to be higher in patients with a high urinary level of type 1 collagen cross-linked N-teropeptide (NTX). No significant difference in lumbar BMD was seen between patients with normal and abnormal ucOC levels. The serum ucOC level returned to normal in 64.9% of patients after they had received additional vitamin K medication.
In conclusion, our findings support the suggestion that not only vitamin K but also bisphosphonate may normalize the serum ucOC level in patients with osteoporosis, as the serum ucOC level is affected by not only vitamin K deficiency but also bone turn-over.
