Vitamin D and orthostatic hypotension

INTRODUCTION: we aimed to investigate on the potential relationship between vitamin D and orthostatic hypotension (OH) in a case-control model in older adults. METHODS: all participants were community-dwelling adults who were not taking vitamin D supplements. Cases were subjects aged 64 or older who were diagnosed with OH at a Falls and Blackout Unit. Controls were age- (within 5 years) and gender-matched subjects who had no history of blackouts, falls or orthostatic dizziness in the preceding year. OH was defined according to standard criteria and was diagnosed with an active stand test. Serum vitamin D [25(OH)D] was measured by radioimmunoassay. RESULTS: seventy-six subjects were included in the analysis (38 controls and 38 cases). Twenty-four in each group were female and mean age was between 78 and 79 years. Subjects with OH had lower serum 25(OH)D compared to controls (mean difference = 20.6 nmol/l, P = 0.0002). Lower vitamin D status was associated with an increased risk of OH after adjustment for season, body mass index, presence of stroke, diabetes and angina (P = 0.035) but not with impaired orthostatic haemodynamics. DISCUSSION: findings suggest that vitamin D may play a role in the aetiology of OH. Further studies will be required to explore on this relationship.