Vitamin D Status in Hemodialysis Transplant Candidates and Living Donors

Study Design: Single-center, cross-sectional descriptive-analytical study. Data Source: Retrospective extraction of medical records. Study Groups: * Hemodialysis patients listed for kidney transplantation. * Healthy living kidney donors. Main Study Variable: • Serum 25-hydroxyvitamin D \[25(OH)D\]. Demographic Variables: * Age * Sex Group Variable: • Clinical status (hemodialysis transplant candidate vs living donor). Statistical Analysis: Data will be analyzed using SPSS software. Continuous variables will be compared using independent t-test (two groups) or ANOVA (if multiple subgroups are analyzed). Regression analysis will be performed to evaluate predictors of serum 25(OH)D levels and its association with relevant clinical variables. Statistical significance will be defined as P \< 0.05.