Effects of 3-Month Vitamin D ₃ Supplementation on Motor and Non-Motor Symptoms in Parkinson’s Disease: A Single-Arm Interventional Study

OBJECTIVES: supplementation on vitamin D status, motor function, sleep quality, and depressive symptoms in patients with Parkinson's disease and vitamin D insufficiency. METHODS: supplementation (7500 IU/day) for three months. Serum 25(OH)D levels and clinical outcomes were assessed at baseline and post-intervention using the Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn and Yahr stage, Pittsburgh Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI). UPDRS total and parts I - III scores improved significantly, while part IV showed no change. PSQI and BDI scores also decreased significantly. However, changes in 25(OH)D levels were not correlated with clinical outcomes, and subgroup analyses showed no differences according to post-intervention vitamin D status. CONCLUSIONS: supplementation improved biochemical and clinical measures in patients with Parkinson's disease and vitamin D insufficiency. However, the increase in vitamin D levels was not associated with clinical changes. CLINICAL IMPLICATIONS: Assessment and correction of vitamin D insufficiency may be considered in Parkinson's disease, but potential clinical benefits should be interpreted cautiously until confirmed by randomized controlled trials.