Vitamin K2 for postmenopausal women with osteoporosis Original paper
In this meta-analysis of mostly low-quality trials, supplementation with vitamin K2 by postmenopausal participants with osteoporosis was associated with improvements in bone mineral density and some biomarkers of bone metabolism.
This Study Summary was published on August 23, 2022.
Background
Because vitamin K2 is a cofactor in the carboxylation of osteocalcin and because carboxylated osteocalcin promotes the mineralization of bone, vitamin K2 supplementation may improve bone mineral density (BMD) in postmenopausal individuals with osteoporosis. Although a number of long-term trials have examined this possibility, a meta-analysis summarizing the results of the available trials was lacking.
The study
This meta-analysis of 9 randomized controlled trials with long-term follow-up periods examined the efficacy and safety of supplementation with vitamin K2 in a total of 6,853 postmenopausal women with osteoporosis (average ages of 54–75). Three trials compared vitamin K2 + calcium to calcium, 3 trials compared vitamin K2 + bisphosphonates to bisphosphonates, 2 trials compared vitamin K2 to calcium, and 1 trial compared vitamin K2 to dietary advice. The daily dose of vitamin K2 was 45 mg in all trials. The duration of the follow-up ranged from 11 months to 4 years.
The primary outcomes were BMD and biomarkers of bone metabolism (undercarboxylated osteocalcin and osteocalcin). The secondary outcomes were the incidence of osteoporotic fractures and adverse effects.
The results
Supplementation with vitamin K2 increased lumbar and forearm BMD, decreased (improved) undercarboxylated osteocalcin, and increased (improved) osteocalcin. The rate of adverse effects (which involved minor gastrointestinal symptoms such as nausea and abdominal pain) was slightly higher with vitamin K2.
The risk of bias was high in 7 trials and low in 2 trials.
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This Study Summary was published on August 23, 2022.