Here is another reason to keep watch on older patients’ vitamin D levels: Too-low levels may contribute to orthostatic hypotension (OH), say researchers from Dokuz Eylül University in Izmir and Bezmialem Vakif University in Istanbul, both in Turkey. Their study of 546 patients found that about 32% of patients with vitamin D deficiency (levels < 20 ng/mL) had OH, compared with about 24% of those whose vitamin D levels were ≥ 20 ng/mL. This study is the largest to date examining vitamin D levels in patients with OH.
The patients were evaluated retrospectively. Data on blood pressure (BP), polypharmacy, cognitive and nutritional status, activities of daily living (ADL), and other patient information were obtained from hospital files. The researchers also had access to laboratory test results, including complete blood count; kidney and liver functions; cholesterol levels; thyroid-stimulating hormone (TSH); A1c; and vitamins B12, D, and folic acid levels.
The first BP measurement was taken after the patient rested for 10 minutes while lying down. Afterwards the patient was raised upright and the measurement was repeated on the same arm after 1 and 3 minutes. A diagnosis of OH was defined as a drop of ≥ 20 mm Hg in systolic BP and/or 10 mm Hg in diastolic BP after changing position.
The analysis revealed that 150 participants had OH (35% of men and 65% of women). Of those with OH, 17% had a drop in systolic BP, almost 20% had a drop in diastolic BP, and about 9% had a drop in both.
Albumin, hemoglobin, calcium, triglyceride, low-density and high-density lipoprotein cholesterol, TSH, A1c, folic acid, and vitamin B12 levels were not significantly different between the groups (P > .05). Only serum levels of vitamin D were found to be lower in patients with OH, compared with those without OH (P = .005). The researchers found a significant relation between serum 25-hydroxy vitamin D levels and both reduced systolic BP (P = .003) and diastolic BP (P = .032).
The researchers point to other studies that have shown vitamin D can affect BP through various mechanisms and that vitamin D deficiency causes endothelial and vascular smooth muscle dysfunction, increasing the risk of cardiovascular events. Studies have also associated vitamin D deficiency with autonomic dysfunction, one of the most important causes of OH.
Orthostatic hypotension is closely linked to mortality and morbidity. In this study, patients with OH had lower scores on ADL indexes. OH can also lead to falls, impaired sleep, depression, and stroke. One study, the researchers say, found that 80,000 hospitalizations each year in the U.S. are due to OH-related falls, syncope, and consequent injuries. They also note that asymptomatic OH is more common in elderly patients than might be suspected: About one-third of patients have OH, although they describe no complaints.
Thus, the researchers conclude, recording changes in postural BP should be part of the routine examination in older patients. And since vitamin D deficiency is both avoidable and correctable, keeping an eye on vitamin D levels is a good idea.
Source
Soysal P, Yay A, Isik AT. Arch Gertontol Geriatr. 2014;59(1):74-77.
doi: 10.1016/j.archger.2014.03.008.