title: Effect of vitamin K on bone mineral density: a meta-analysis of randomized controlled trials.
abstract: A number of randomized controlled trials (RCTs) examining the role of vitamin K on bone mineral density (BMD) have yielded inconsistent results. We performed a meta-analysis of these trials to assess the effect of vitamin K on BMD. We searched MEDLINE, EMBASE and CENTRAL for relevant studies of RCTs examining the role of vitamin K on BMD. Data on participants, interventions, and outcomes were extracted and the quality of all included trials assessed. Primary outcomes for analysis were absolute changes in BMD (mg/cm(2)) at the lumbar spine and femoral neck. Relative changes (percentage change) in BMD at the lumbar spine were also assessed. Vitamin K supplementation was shown to be efficacious in increasing BMD at the lumbar spine but not the femoral neck. The weighted mean difference (WMD) in BMD absolute change was 21.60 mg/cm(2) [95% confidence interval (CI) 3.63, 39.56] at the lumbar spine and 0.25 mg/cm(2) (95% CI -2.64, 3.14) at the femoral neck. The WMD in BMD relative change was 1.27% (95% CI 0.47, 2.06) at the lumbar spine and 0.17 (95% CI -0.21, 0.54) at the femoral neck. Subgroup analysis revealed that ethnic difference, gender, and vitamin K type were associated with variable effects on BMD at the lumbar spine. The modest overall treatment effects for vitamin K on BMD observed in this review may be biased and should be interpreted with caution. Further studies are required to address factors relating to the observed effects of vitamin K on BMD.
authors.affiliation: School of Public Health, Anhui Medical University, 81 Mei Shan Road, Hefei 230032, Anhui, China.
authors.forename: Yanfu
authors.initials: Y
authors.lastname: Fang
authors.forename: Chuanlai
authors.initials: C
authors.lastname: Hu
authors.forename: Xingyong
authors.initials: X
authors.lastname: Tao
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Wan
authors.forename: Fangbiao
authors.initials: F
authors.lastname: Tao
mesh_terms: D000328:Adult; D000368:Aged; D015519:Bone Density / Q000187:drug effects*; D019587:Dietary Supplements; D005260:Female; D005272:Femur Neck / Q000187:drug effects; D006801:Humans; D008159:Lumbar Vertebrae / Q000187:drug effects; D008875:Middle Aged; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic; D014812:Vitamin K / Q000494:pharmacology*
chemical_list: D014812:Vitamin K