Effects of vitamin D3 on selected biochemical parameters of nutritional status, inflammation, and cardiovascular disease in patients undergoing long-term hemodialysis

INTRODUCTION Vitamin D-3 has diverse biological effects extending beyond the maintenance of calcium and phosphorus homeostasis and ensuring the proper functioning of the body. OBJECTIVES This study evaluated the levels of vitamin D-3 and its association with nutritional status, immunological activity, and selected markers of cardiovascular disease in patients on long-term hemodialysis (HD). PATIENTS AND METHODS We measured 25-hydroxyvitamin D-3 (25(OH)D-3) levels in a group of 84 patients (mean age, 65 years; average time on dialysis, 32.5 months) and investigated correlations between 25(OH)D-3 levels and the following parameters: albumin, body mass index, hemoglobin (Hb), interleukin 6 (IL-6), interleukin 10, C-reactive protein, asymmetric dimethylarginine (ADMA), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and comorbidity score. RESULTS A mean 25(OH)D-3 level was 15.4 +/- 7.2 ng/ml and only 5% of patients had 25(OH)D-3 levels above the normal value of 30 ng/ml. There was no statistically significant difference in 25(OH)D-3 levels between women and men (P = 0.06). A negative correlation was observed between 25(OH)D-3 and IL-6 (R = -0.31, P = 0.009) and ADMA (R = -0.26, P = 0.03), as well as a positive correlation between 25(OH)D-3 and Hb (R = 0.21, P = 0.05). There was no association between 25(OH)D-3 levels and nutritional status. CONCLUSIONS A significant vitamin D-3 deficiency observed in the majority of patients undergoing long-term HD contributes to the development of chronic inflammation, anemia, and indirectly, to endothelial cell injury.