Objective: To evaluate the impact of vitamin D supplementation on cognitive outcomes, quality of life and dyskinesia severity in PD through a systematic review and meta-analysis of randomised controlled trials.

Background: Inflammation-driven oxidative stress is thought to contribute to nigrostriatal degeneration in PD. Immunomodulatory and potential neuroprotective effects of vitamin D is hypothesised to mitigate inflammation-related neuronal injury. While PD is characterised primarily by progressive motor impairment, patients frequently develop cognitive decline and dyskinesias as the disease advances, along with motor function deterioration culminating in reduced quality of life.

Method: A systematic search of PubMed, Scopus, and the Cochrane Library was conducted to identify randomized controlled trials (RCTs) evaluating Vitamin D supplementation in patients with Parkinson’s Disease (PD). Three RCTs (N=282) investigated dyskinesia severity, three (N=192) assessed cognitive outcomes, and two (N=161) evaluated quality of life (QOL). Outcomes were measured using the Mini-Mental State Examination (MMSE) or Montreal cognitive assessment (MoCA) for cognition, PDQ-39 total scores for QOL, and Unified Parkinson’s Disease Rating Scale- IVB (UPDRS-IVB) or Modified Abnormal Involuntary Movement Scale (mAIMS-without mental task) for dyskinesia. Assessments were conducted at baseline and following various post-intervention follow-up periods.

Results: Meta-analysis revealed that Vitamin D supplementation did not yield statistically significant improvements across the primary outcomes. For dyskinesia severity, although one RCT reported positive results, the pooled analysis of three trials was non-significant (SMD -0.537; 95% CI -1.79 to 0.73). Quality of life outcomes from two RCTs similarly failed to reach statistical significance (SMD -0.75; 95% CI -5.85 to 6.05). Regarding cognitive function, pooled data from two eligible RCTs showed no significant benefit (SMD -0.796; 95% CI -5.680 to -4.088). Methodological quality across the studies was high, with a low overall risk of bias as determined by the RoB 2 tool.

Conclusion: Vitamin D supplementation does not confer a statistically significant improvement in cognition, quality of life or dyskinesia severity. High-quality RCTs are required to clarify the potential therapeutic role of vitamin D in PD.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/impact-of-vitamin-d-supplementation-on-cognitive-function-quality-of-life-and-dyskinesia-in-parkinsons-disease-a-systematic-review-and-meta-analysis/