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 D 3 (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 .