Low Vitamin K Status and Risk of Chronic Obstructive Pulmonary Disease. A post-hoc analysis of two observational studies | Data from the CODEX-P and DanFunD study.

<bold>Background:</bold> Vitamin K is a cofactor necessary for the biological activity of proteins like Matrix Gla Protein (MGP), which reduce calcification and help preserve lung function. This study aims to determine whether chronic obstructive pulmonary disease (COPD) is associated with low vitamin K, secondary whether the level of vitamin K is associated with COPD severity or mortality. <bold>Methods:</bold> The plasma concentration of dephosphorylated uncarboxylated (dp-uc) MGP was used as an inverse biomarker for vitamin K in 98 COPD patients from the CODEX-P COPD study and 986 controls from the DanFunD study. Low vitamin K status was defined as upper quartile of dp ucMGP (>589 pmol/L). Using a logistic regression model, we examined whether low vs high/moderate vitamin K status increased the odds-ratio (OR) of having COPD. Secondary analyses examined the association between low vitamin K status and COPD severity and all-cause mortality, in the COPD cohort, using a Welch’s t-test and log-rank test. <bold>Results:</bold> Low vitamin K status was associated with increased odds of having COPD, OR 9.7(95%CI [5.5 to 17.5], P<0.001). We found no associations between low vitamin K and COPD severity (est. -0.03, P=0.7; 95%CI [-0.2 to 0.1]), or all-cause mortality (P=0.5). <bold>Conclusion:</bold> Low vitamin K status was associated with substantially higher odds of having COPD compared to high/moderate vitamin K status. No association was found between low vitamin K status and COPD severity, or all-cause mortality. Further studies are needed to determine if vitamin K plays a role in the pathophysiology of COPD and whether supplement therapy is indicated.