Abstract

BACKGROUND: orthostatic hypotension (OH) that occurs within, or at, 1 minute of standing is associated with higher risk of falls, myocardial infarction, syncope and mortality, compared to OH that occurs after 1 minute of standing. Whether vitamin D deficiency increases the risk of OH is controversial. METHODS: this was a cross-sectional analysis of 3,620 older, community-dwelling men. Multinomial, multiple logistic regression models were used to calculate the risk of OH across categories of vitamin D status (deficient [<25 nmol/l], insufficient [≥25-<50 nmol/l] and sufficient [≥50 nmol/l]) and parathyroid hormone quintile. RESULTS: men with vitamin D deficiency were more likely to have OH that occurred within 1 minute of standing in univariate logistic regression (OR 1.88, 95% CI 1.40-2.53) and multinomial, multiple logistic regression (OR 1.51, 95% CI 1.06-2.15), compared to men with sufficient levels of vitamin D. Vitamin D insufficiency was not associated with the risk of OH. Elevated parathyroid hormone was not associated with risk of OH. CONCLUSION: the absence of an association between vitamin D insufficiency and risk of OH and the presence of an association between vitamin D deficiency and risk of OH suggest that there may be a threshold effect; it is only below a particular level of vitamin D that risk of OH is increased. In this cohort, the threshold was <25 nmol/l. Future work should investigate whether treating vitamin D deficiency can improve postural blood pressure or if preventing vitamin D deficiency reduces the incidence of OH.