Vitamin D deficiency in Parkinson's disease patients with orthostatic hypotension

Objectives: The purpose of our study was to investigate the associations between serum vitamin D3 levels and orthostatic hypotension (OH) in patients with Parkinson's disease (PD). Materials and methods: Fifty-five patients with PD were enrolled in this study. Blood pressure (BP) measurements were gathered while the patients were in the supine position and while standing up. Then, the patients were divided into two groups: PD patients with and without OH. We compared the levels of serum 25-hydroxyvitamin D3 and 1, 25-dihydroxyvitamin D₃ (calcitriol) between the two groups. Results: Serum 25-hydroxyvitamin D and calcitriol levels were significantly decreased in patients with OH compared with those without OH. The systolic and diastolic BPs and symptom severities significantly negatively correlated with the serum 25-hydroxyvitamin D and calcitriol levels. Conclusions: Although the underlying mechanism for this association is not fully understood, our results suggest that low vitamin D status is associated with OH in patients with PD.