The effect of vitamin MK-7 on bone mineral density and microarchitecture in postmenopausal women with osteopenia, a 3-year randomized, placebo-controlled clinical trial.

Abstract

Vitamin K is a cofactor in the carboxylation of osteocalcin (OC) and carboxylated OC promotes mineralization of bone. Clinical studies suggest that vitamin K2 prevents bone loss. The aim of the study was to investigate the effect of vitamin K2 as an add-on to calcium and vitamin D supplementation on osteocalcin, bone mass, and microarchitecture in postmenopausal women. We conducted a randomized placebo-controlled double-blinded clinical trial, including 142 postmenopausal women with osteopenia who received vitamin K2 (375μg MK-7) or placebo daily for 3years. Both groups received vitamin D3 (38μg/day) and calcium (800mg/day). We measured bone turnover markers in serum and bone mineral density and microarchitecture by DXA and HRpQCT. Undercarboxylated osteocalcin decreased in the MK-7-group (- 65.2 ± 23.5%) (mean ± SD) compared with the placebo group (- 0.03 ± 38.5%), p < 0.01 after 1year. After 3years, aBMD decreased at all sites without differences between the MK-7 and placebo-treated women (p > 0.09). aBMD decreased at the total hip by 1.5 ± 2.5% and 2.4 ± 2.7% in the MK-7 and the placebo groups, respectively, at the femoral neck by 1.5 ± 3.5% and 1.0 ± 5.0% in the MK-7 and the placebo groups, respectively, and at the lumbar spine by 1.8 ± 3.9% and 1.1 ± 3.1% in the MK-7 and the placebo groups, respectively. Changes in bone turnover markers were also similar between the two groups.We have previously reported improved microarchitecture with MK-7 after 1year. However, changes in microstructure over 3years were similar between the two groups, as assessed by both HRpQCT and DXA trabecular bone score. Treatment with MK-7375μg daily as an add-on to calcium and vitamin D increased carboxylation of osteocalcin. However, treatment of postmenopausal women with osteopenia for 3years did not affect biochemical markers of bone turnover, bone mineral density, or bone microarchitecture. The study was registered at Clinicaltrial.gov : NCT01922804 .