The combined effect of vitamin K and calcium on bone mineral density in humans: a meta-analysis of randomized controlled trials

Role of vitamins beyond vitamin D3 in bone health and osteoporosis (Review)

The objective of the present review was to summarize the molecular mechanisms associated with the effects of the vitamins A, C, E and K, and group B vitamins on bone and their potential roles in the development of osteoporosis. Epidemiological findings have demonstrated an association between vitamin deficiency and a higher risk of developing osteoporosis; vitamins are positively related to bone health upon their intake at the physiological range. Excessive vitamin intake can also adversely affect bone formation, as clearly demonstrated for vitamin A. Vitamins E (tocopherols and tocotrienols), K2 (menaquinones 4 and 7) and C have also been shown to promote osteoblast development through bone morphogenetic protein (BMP)/Smad and Wnt/β‑catenin signaling, as well as the TGFβ/Smad pathway (α‑tocopherol). Vitamin A metabolite (all‑trans retinoic acid) exerts both inhibitory and stimulatory effects on BMP‑ and Wnt/β‑catenin‑mediated osteogenesis at the nanomolar and micromolar range, respectively. Certain vitamins significantly reduce receptor activator of nuclear factor kappa‑B ligand (RANKL) production and RANKL/RANK signaling, while increasing the level of osteoprotegerin (OPG), thus reducing the RANKL/OPG ratio and exerting anti‑osteoclastogenic effects. Ascorbic acid can both promote and inhibit RANKL signaling, being essential for osteoclastogenesis. Vitamin K2 has also been shown to prevent vascular calcification by activating matrix Gla protein through its carboxylation. Therefore, the maintenance of a physiological intake of vitamins should be considered as a nutritional strategy for the prevention of osteoporosis.

[Exercise therapy and basic treatment for osteoporosis]

Physical training is an important component in the prophylaxis of osteoporosis and the prevention of fractures. Physical training not only has a direct effect on muscle strength and muscular performance, but also on the risk of falling and the fear of falling. Therefore, physical training is also an integral part of the basic treatment for osteoporosis. The recommendations for basic treatment are an adequate intake of nutrients, including protein in particular. The intake of calcium and vitamin D in sufficient quantities is also important and, in the case of specific drug therapy, also to avoid side effects and to ensure the therapeutic effect. This article summarizes the recommendations of the updated S3 guideline on the diagnosis and treatment of osteoporosis and explains the background for the recommendations included.

Clinical efficacy of denosumab, teriparatide, and oral bisphosphonates in the prevention of glucocorticoid-induced osteoporosis: a systematic review and meta-analysis

BACKGROUND

Continuous use of glucocorticoids (GCs) has become the primary cause of secondary osteoporosis. Bisphosphonate drugs were given priority over denosumab and teriparatide in the 2017 American College of Rheumatology (ACR) guidelines but have a series of shortcomings. This study aims to explore the efficacy and safety of teriparatide and denosumab compared with those of oral bisphosphonate drugs.

METHODS

We systematically searched studies included in the PubMed, Web of Science, Embase, and Cochrane library databases and included randomized controlled trials that compared denosumab or teriparatide with oral bisphosphonates. Risk estimates were pooled using both fixed and random effects models.

RESULTS

We included 10 studies involving 2923 patients who received GCs for meta-analysis, including two drug base analyses and four sensitivity analyses. Teriparatide and denosumab were superior to bisphosphonates in increasing the bone mineral density (BMD) of the lumbar vertebrae [teriparatide: mean difference [MD] 3.98%, 95% confidence interval [CI] 3.61-4.175%, P = 0.00001; denosumab: MD 2.07%, 95% CI 0.97-3.17%, P = 0.0002]. Teriparatide was superior to bisphosphonates in preventing vertebral fractures and increasing hip BMD [MD 2.39%, 95% CI 1.47-3.32, P < 0.00001]. There was no statistically significant difference between serious adverse events, adverse events, and nonvertebral fracture prevention drugs.

CONCLUSIONS

Teriparatide and denosumab exhibited similar or even superior characteristics to bisphosphonates in our study, and we believe that they have the potential to become first-line GC-induced osteoporosis treatments, especially for patients who have previously received other anti-osteoporotic drugs with poor efficacy.

Efficacy and safety of vitamin K2 for postmenopausal women with osteoporosis at a long-term follow-up: meta-analysis and systematic review

INTRODUCTION

Vitamin K2 supplementation has been revealed to be effective in the prevention and treatment of osteoporosis in Japan, but further proof for the effectiveness of this practice is still needed.

OBJECTIVE

To investigate whether vitamin K2 supplementation plays a role in maintaining bone mineral density (BMD) and reducing the incidence of fractures for postmenopausal women with osteoporosis at a long-term follow-up.

MATERIALS AND METHODS

We searched systematically throughout the databases of PubMed, Cochrane library, and EMBASE from the dates of their inception to November 16 2021 in this meta-analysis and systematic review, using keywords vitamin K2 and osteoporosis.

RESULTS

Nine RCTs with 6853 participants met the inclusion criteria. Vitamin K2 was associated with a significantly increased percentage change of lumbar BMD and forearm BMD (WMD 2.17, 95% CI [1.59-2.76] and WMD 1.57, 95% CI [1.15-1.99]). There were significant differences in undercarboxylated osteocalcin (uc-OC) reduction (WMD -0.96, 95% CI [-0.70 to 0.21]) and osteocalcin (OC) increment (WMD 26.52, 95% CI [17.06-35.98]). Adverse reaction analysis showed that there seemed to be higher adverse reaction rates in the vitamin K2 group (RR = 1.33, 95% CI [1.11-1.59]), but no serious adverse events related to vitamin K2 supplementation.

CONCLUSION

This meta-analysis and systematic review seemed to support the hypothesis that vitamin K2 plays an important role in the maintenance and improvement of BMD, and it decreases uc-OC and increases OC significantly at a long-term follow-up. Vitamin K2 supplementation is beneficial and safe in the treatment of osteoporosis for postmenopausal women.

Efficacy of vitamin K2 in the prevention and treatment of postmenopausal osteoporosis: A systematic review and meta-analysis of randomized controlled trials

Introduction

Vitamin K (VK) as a nutrient, is a cofactor in the carboxylation of osteocalcin (OC), which can bind with hydroxyapatite to promote bone mineralization and increase bone strength. However, some studies have been inconsistent on whether vitamin K2 (VK2) can maintain or improve bone mineral density (BMD) and reduce the incidence of fractures in postmenopausal women. Therefore, the main objective of this meta-analysis was to determine the effect of VK2 as a nutritional supplement on BMD and fracture incidence in postmenopausal women.

Methods

We searched PubMed, EMBASE, and Cochrane Library databases (published before March 17, 2022) and then extracted and pooled data from all randomized controlled trials (RCTs) that met the inclusion criteria.

Results

Sixteen RCTs with a total of 6,425 subjects were included in this meta-analysis. The overall effect test of 10 studies showed a significant improvement in lumbar spine BMD (BMD LS) (P = 0.006) with VK2. The subgroup analysis of VK2 combination therapy showed that BMD LS was significantly maintained and improved with the administration of VK2 (P = 0.03). The overall effect test of the six RCTs showed no significant difference in fracture incidence between the two groups (RR=0.96, P=0.65). However, after excluding one heterogeneous study, the overall effect test showed a significant reduction in fracture incidence with VK2 (RR = 0.43, P = 0.01). In addition, this meta-analysis showed that VK2 reduced serum undercarboxylated osteocalcin (uc-OC) levels and the ratio of uc-OC to cOC in both subgroups of VK2 combined intervention and alone. However, for carboxylated osteocalcin (cOC), both subgroup analysis and overall effect test showed no significant effect of VK2 on it. And the pooled analysis of adverse reactions showed no significant difference between the VK2 and control groups (RR = 1.03, 95%CI 0.87 to 1.21, P = 0.76).

Conclusions

The results of this meta-analysis seem to indicate that VK2 supplementation has a positive effect on the maintenance and improvement of BMD LS in postmenopausal women, and it can also reduce the fracture incidence, serum uc-OC levels and the ratio of uc-OC to cOC. In conclusion, VK2 can indirectly promote bone mineralization and increase bone strength.