The effect of vitamin D replacement therapy on insulin resistance: a retrospective study

Aims: This study retrospectively evaluated the effect of a 3-month vitamin D replacement therapy in patients diagnosed with insulin resistance (IR) and low vitamin D levels. The relationship between changes in vitamin D levels and IR was investigated. Methods: A total of 98 patients with low serum vitamin D levels and HOMA-IR >2.5, who were admitted to the internal medicine outpatient clinic between January 1 and December 31, 2023, were included in this retrospective study. Sociodemographic characteristics and pre-and post-treatment biochemical parameters were obtained from medical records. Post-supplementation levels of vitamin D, glucose, insulin, and HOMA-IR were analyzed. Pre-and post-treatment values were compared using paired t-tests. The relationship between changes in vitamin D levels and HOMA-IR scores was assessed using Spearman correlation analysis. Results: Of the 98 patients, 85.7% were female and 14.3% were male, with a mean age of 39.09±11.45 years. A significant reduction in HOMA-IR score was observed after vitamin D supplementation (pre: 4.54±2.05; post: 3.01±1.28; p