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

INTRODUCTION: Vitamin D3 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 D3 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 D3 (25(OH)D3) levels in a group of 84 patients (mean age, 65 years; average time on dialysis, 32.5 months) and investigated correlations between 25(OH)D3 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)D3 level was 15.4 ±7.2 ng/ml and only 5% of patients had 25(OH)D3 levels above the normal value of 30 ng/ml. There was no statistically significant difference in 25(OH)D3 levels between women and men (P = 0.06). A negative correlation was observed between 25(OH)D3 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)D3 and Hb (R= 0.21, P = 0.05). There was no association between 25(OH)D3 levels and nutritional status. CONCLUSIONS: A significant vitamin D3 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.