Abstract
Objectives Recent studies have suggested that vitamin K may exert significant effects on the central nervous system. The present study investigates the relationship between vitamin K plasmatic levels and cognitive functions in elderly patients on oral anticoagulant therapy (OAT). Design At the Thrombosis Centre of Haematology, “Sapienza” University of Rome, 85 patients on OAT, aged between 75 and 92, were randomly enrolled in the study. Patients were on OAT with vitamin K antagonists (VKAs). Vitamin K1 concentrations were determined using standardized High-Performance Liquid Chromatography (HPLC). Cognitive functions were assessed using the Milan Overall Dementia Assessment (MODA). Results MODA scores are positively correlated to vitamin K1 concentration. Patients with vitamin K1 below 0.100 μg/L and between 0.100 and 0.400 μg/L and between 0.100 and 0.400 μg/L and between 0.100 and 0.400 p < 0.001). Even long-term OAT (>10 years) does not affect MODA scores. Education seems to exert a greater role on the cognitive status in comparison with aging. Conclusions The study shows a positive association between vitamin K1 concentration and cognitive status in elderly patients (≥75 years) on OAT. The relationship between vitamin K1 concentration and MODA scores is described by a linear model. Cognitive status is not influenced by the duration of OAT but by the years of education.
Highlights
Vitamin K includes a group of lipid-soluble molecules based on a common 2-methyl-1,4-naphtoquinone ring but with a different side chain at the 3-position [1,2,3]
We evaluated the correlations between, on the one hand, Milan Overall Dementia Assessment (MODA) scores and vitamin K1 levels, and, on the other hand, education, age, oral anticoagulant therapy (OAT) length, and comorbidities
Studies on animal models have suggested that vitamin K may be involved in memory consolidation
Summary
Vitamin K includes a group of lipid-soluble molecules based on a common 2-methyl-1,4-naphtoquinone ring but with a different side chain at the 3-position [1,2,3]. MKs are produced by bacteria as provitamins and present unsaturated 5-carbon (prenyl) side chains at the 3-position [1,2,3]. MK-4, is not commonly produced by bacteria, but synthesised from vitamin K1 [2, 3]. Vitamin K has a key role in the carboxylation of glutamate residues in proteins leading to gamma-carboxyglutamate (Gla) residues. Gla-proteins are involved in blood coagulation (coagulation factors II, VII, IX, and X and protein C, S, and Z), as well as in bone and vascular metabolism (osteocalcin and growth arrest-specific protein 6, Gas-6, respectively) [1, 2]
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