Serum 25-hydroxyvitamin D and orthostatic hypotension in old people: the Pro.V.A. study.

Interest in the association between serum 25-hydroxyvitamin D (25OHD) and blood pressure has increased because recent research showed a close relationship between them, but there is still little information on the possible association between 25OHD and orthostatic hypotension. The aim of this study was to explore the relationship of 25OHD levels with any presence of orthostatic hypotension in a large group of older people. This study was part of the Progetto Veneto Anziani (Pro.V.A.), an Italian population-based cohort study involving people aged >65 years. In this cross-sectional work, we considered 2640 (1081 men and 1559 women) with a mean age of 73.8±6.8 years. Orthostatic hypotension was defined as a drop of ≤20 mm Hg in systolic or ≤10 mm Hg in diastolic blood pressure <3 minutes of orthostatism. Orthostatic hypotension was identified in 32.2% of the sample. The prevalence of orthostatic hypotension was higher in individuals with 25OHD levels <50 nmol/L, but this trend was not significant (P=0.13). Individuals who had orthostatic hypotension had significantly lower 25OHD levels than those who did not (75.0±51.4 versus 82.6±54.0 nmol/L; P<0.0001). On logistic regression analysis, the greater likelihood of individuals with lower 25OHD levels having orthostatic hypotension was no longer statistically significant after adjusting for potential confounders (odds ratio, 1.08; 95% confidence interval, 0.77-1.51; P=0.67 for people with 25OHD levels ≤25 nmol/L; odds ratio, 1.01; 95% confidence interval, 0.78-1.32; P=0.92 for those with 25OHD levels between 25 and 50 nmol/L). In conclusion, vitamin D is not significantly associated with any orthostatic hypotension in older people.