The association of vitamin K status with lung function and disease in a general population

INTRODUCTION: Matrix Gla protein (MGP) is an inhibitor of lung tissue calcification. The plasma level of dephosphorylated-uncarboxylated MGP (dp-ucMGP) is a biomarker of vitamin K status. The present study assessed whether lower vitamin K status (reflected by higher dp-ucMGP) was associated with lung function and lung disease/symptoms. METHODS: A general population sample of 4092 individuals, aged 24 to 77 years, underwent a health examination including questionnaires, spirometry and measurements of plasma dp-ucMGP. Associations of dp-ucMGP with lung function and self-reported disease/symptoms were estimated using regression models adjusted for age, sex and height. Associations were expressed as β-estimates or odds ratios (ORs) per doubling in dp-ucMGP. RESULTS: Lower vitamin K status (higher dp-ucMGP) was associated with lower forced expiratory volume in 1 s (FEV(1)) (98 mL; 95% CI: 54–141 mL) and lower forced vital capacity (FVC) (136 mL; 95% CI: 85–187 mL). Dp-ucMGP was not associated with the FEV(1)/FVC ratio (0.0 percentage points higher than the expected value; 95% CI: −1.0–1.0). Furthermore, lower vitamin K status was associated with COPD (OR 2.24, 95% CI: 1.53–3.27), wheezing (OR 1.81, 95% CI: 1.44–2.28) and asthma (OR 1.44, 95% CI: 1.12–1.83). CONCLUSION: Lower vitamin K status was associated with lower ventilatory capacity (lower FEV(1) and FVC), and with higher risk of self-reported asthma, COPD and wheezing. Vitamin K status was not associated with airflow obstruction (FEV(1)/FVC ratio).