Efficacy of Vitamin D in Post-Stroke Cognitive Impairment

Post-stroke cognitive impairment (PSCI) is a prevalent and debilitating sequela of stroke, posing a significant burden on patients and healthcare systems. Emerging evidence suggests that Vitamin D deficiency is associated with an increased risk of cognitive decline and neuroinflammation. However, the therapeutic potential and underlying immunological mechanisms of Vitamin D supplementation in PSCI remain unclear. This study is a randomized, double-blind, placebo-controlled trial designed to evaluate the efficacy of Vitamin D supplementation in improving cognitive function among patients with PSCI. The primary objective is to determine whether high-dose Vitamin D administration can significantly enhance cognitive performance compared to a placebo group. Secondary objectives include assessing the effects on serum inflammatory markers (such as IL-6, TNF-α, and IL-10) and regulatory T cells (Tregs), thereby exploring the potential immune-modulatory pathways. Eligible participants will be randomly assigned to receive either oral Vitamin D (e.g., 5000 IU/day) or an identical placebo for a duration of \[e.g., 6 months\]. Cognitive function will be assessed using standardized neuropsychological tests, including the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). Blood samples will be collected at baseline and post-intervention to measure changes in immune-related biomarkers. The findings of this trial will provide critical evidence regarding the role of Vitamin D as a potential adjunctive therapy for PSCI and elucidate the connection between vitamin D status and post-stroke immune regulation.

Inclusion Criteria: * Age: Aged 18 to 80 years (inclusive). * Diagnosis: First-ever ischemic or hemorrhagic stroke, confirmed by brain CT or MRI within 1 week of onset. * Time Window: Post-stroke duration between 3 months and 24 months. * Cognitive Status: Presence of cognitive impairment, defined as a Montreal Cognitive Assessment (MoCA) score \< 26 (or your specific cutoff) at screening. * Stability: Clinically stable condition, without recurrent stroke or transient ischemic attack (TIA) in the past 3 months. * Consent: Ability to provide written informed consent by the participant or their legal representative. * Compliance: Willingness and ability to comply with the study protocol and follow-up visits. Exclusion Criteria: * Severe Disability: Pre-morbid or current modified Rankin Scale (mRS) score \> 3. * Other CNS Diseases: Presence of other neurological diseases that could cause cognitive decline (e.g., Parkinson's disease, epilepsy, brain tumor, or severe traumatic brain injury). * Psychiatric Disorders: History of major psychiatric disorders (e.g., schizophrenia, severe depression) that may interfere with cognitive testing. * Vitamin D Status: Known history of hypercalcemia, hypercalciuria, or sarcoidosis; or current use of vitamin D supplements (\>800 IU/day) or calcium supplements within the past 3 months. * Severe Comorbidities: Severe dysfunction of heart, liver, or kidney (e.g., ALT/AST \> 3x ULN, eGFR \< 30 mL/min/1.73m²). * Life Expectancy: Life expectancy less than 6 months due to malignant tumors or other terminal illnesses. * Allergy: Known allergy or hypersensitivity to vitamin D or any components of the study formulation. * Participation: Participation in another interventional clinical trial within the past 30 days.