Uncarboxylated matrix Gla-protein: A biomarker of vitamin K status and cardiovascular risk

Background: Dephosphorylated uncarboxylated matrix Gla-protein (dp-ucMGP) is a biomarker of functional vitamin K status. High plasma dp-ucMGP concentrations reflect a low vitamin K status and have been related to vascular calcification. Our aims were to assess plasma levels of dp-ucMGP and their association with cardiovascular risk in a general population. Methods: Plasma dp-ucMGP measurements were performed using the IDS-iSYS InaKtif MGP assay in 491 consecutive participants in a Danish general population study (229 males and 262 females, aged 19–71 years). Multivariable linear and logistic regressions were used to assess the association between dp-ucMGP levels and cardiovascular risk factors. Results: Mean ± standard deviation (SD) for dp-ucMGP was 465 ± 181 pmol/L, and upper 95th percentile was 690 pmol/L. In logistic regression analyses, an increase in dp-ucMGP category (<300, 300–399, 400–499, ≥500 pmol/L) was positively associated with obesity, odds ratio (OR) 2.27 (95% confidence interval (CI) 1.54–3.33), history of cardiovascular disease, OR 1.77 (CI 1.02–3.05), and above-median estimated pulse wave velocity (ePWV), OR 1.54 (CI 1.21–1.96), when adjusted for age, sex, and lifestyle factors. 1 SD increase in diastolic and systolic blood pressure (BP) corresponded to a 5.5% (CI 2.9–8.0%) and 4.7% (CI 2.1–7.4%) increase in dp-ucMGP, respectively, when adjusted for age and sex. Conclusion: Plasma dp-ucMGP levels were positively associated with obesity, BP, ePWV, and history of cardiovascular disease. These findings support that dp-ucMGP is a biomarker of cardiovascular risk, and that vitamin K status could play a role in vascular calcification. The strong association with obesity deserves further attention.