Plain language summary
Osteoporosis is the most common bone disease leading to weakening of the bones and is particularly prevalent in postmenopausal women. Osteoporosis-related fractures cause severe pain and disability, and strains on the healthcare systems. The typical treatment in postmenopausal osteoporosis involves the prescription of oral bisphosphonate medications. An important regulator in bone health is Vitamin K. Low vitamin K levels and intake are linked to reduced bone mineral density (BMD) and increased fractures. Some findings suggest that a combination treatment of bisphosphonate and vitamin K2 (MK-4) may enhance treatment efficacy and hence this randomised placebo-controlled trial sought further evidence. The study enrolled 105 women, between 55–85 years old, with osteoporosis and low vitamin K status. The women received either vitamin K1 (1 mg/day), vitamin K2 arm (MK-4; 45 mg/day) or a placebo for 18 months, alongside oral bisphosphonate and calcium and/or vitamin D treatment. Outcomes were measured in bone mineral density (BMD), structural characteristics of the hips (hip geometry) and bone turnover markers (BTMs). 91 candidates completed the trial. The results showed that the combination of vitamin K1 or MK-4 and oral bisphosphonate did not lead to significant improvement in bone mineral density or bone turnover. However it showed significant changes in hip geometry in the vitamin K1 group, suggesting a potential synergy here. Whereby there were positive trends in BMD too with vitamin K1 supplementation, the results did not reach significance. In the discussion the authors review the outcomes in the context of existing research, suggesting that perhaps a longer duration of treatment with vitamin K may be required to boost mineralisation and BMD outcomes. The effect of MK-4 on bone cells may also have been hindered by its poor bioavailability and the suppression of bone remodelling caused by long-term bisphosphonate therapy. Larger and longer-term studies are needed to confirm the effects of Vitamin K on hip remodelling and prevention of bone fractures and help clarify the mixed results in existing research.
Abstract
UNLABELLED This study assessed whether vitamin K, given with oral bisphosphonate, calcium and/or vitamin D has an additive effect on fracture risk in post-menopausal women with osteoporosis. No difference in bone density or bone turnover was observed although vitamin K1 supplementation led to a modest effect on parameters of hip geometry. PURPOSE Some clinical studies have suggested that vitamin K prevents bone loss and may improve fracture risk. The aim was to assess whether vitamin K supplementation has an additive effect on bone mineral density (BMD), hip geometry and bone turnover markers (BTMs) in post-menopausal women with osteoporosis (PMO) and sub-optimum vitamin K status receiving bisphosphonate, calcium and/or vitamin D treatment. METHODS We conducted a trial in 105 women aged 68.7[12.3] years with PMO and serum vitamin K1 ≤ 0.4 µg/L. They were randomised to 3 treatment arms; vitamin K1 (1 mg/day) arm, vitamin K2 arm (MK-4; 45 mg/day) or placebo for 18 months. They were on oral bisphosphonate and calcium and/or vitamin D. We measured BMD by DXA, hip geometry parameters using hip structural analysis (HSA) software and BTMs. Vitamin K1 or MK-4 supplementation was each compared to placebo. Intention to treat (ITT) and per protocol (PP) analyses were performed. RESULTS Changes in BMD at the total hip, femoral neck and lumbar spine and BTMs; CTX and P1NP did not differ significantly following either K1 or MK-4 supplementation compared to placebo. Following PP analysis and correction for covariates, there were significant differences in some of the HSA parameters at the intertrochanter (IT) and femoral shaft (FS): IT endocortical diameter (ED) (% change placebo:1.5 [4.1], K1 arm: -1.02 [5.07], p = 0.04), FS subperiosteal/outer diameter (OD) (placebo: 1.78 [5.3], K1 arm: 0.46 [2.23] p = 0.04), FS cross sectional area (CSA) (placebo:1.47 [4.09],K1 arm: -1.02[5.07], p = 0.03). CONCLUSION The addition of vitamin K1 to oral bisphosphonate with calcium and/or vitamin D treatment in PMO has a modest effect on parameters of hip geometry. Further confirmatory studies are needed. TRIAL REGISTRATION The study was registered at Clinicaltrial.gov:NCT01232647.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
