AIM: To investigate the effect of vitamin K2 (menatetrenone) treatment on bone mineral density (BMD) and a bone metabolic marker (osteocalcin) in postmenopausal women with osteoporosis living in Indonesia.

METHODS: A double-blind randomized placebo-controlled study of 63 postmenopausal women with osteoporosis. The vitamin K2 group (n = 33) received 45 mg menatetrenone and 1500 mg calcium carbonate per day and the control group (n = 30) received placebo and 1500 mg calcium carbonate per day for 48 weeks. BMD of lumbal spine (L2-L4), osteocalcin (OC) and undercarboxylated OC were measured before, 24 and 48 weeks after initiation of the treatment.

RESULTS: After 48 weeks of treatment, the mean percentage change of lumbar BMD in the vitamin K2 group was significantly higher (P<0.05) than that of the control group. The undercarboxylated OC level decreased by 55.9% in the menatetrenone group and 9.3% in the control group compared with the baseline level. The difference between the two groups was significant (P<0.01). The adverse events were three minor gastrointestinal cases, which subsided after temporary cessation of therapy.

CONCLUSIONS: Treatment with 45 mg vitamin K2 with 1500 mg calcium per day for postmenopausal women with osteoporosis for 48 weeks resulted in a significant increase in lumbar BMD and a significant decrease in undercarboxylated OC levels.