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VitDISH: Vitamin D did not reduce BP in patients with isolated systolic hypertension
In a new study, vitamin D supplementation did not lower BP or improve other markers of vascular health in older patients with isolated systolic hypertension.
Miles D. Witham, PhD, and colleagues conducted the randomized, double blind, parallel-group, placebo-controlled VitDISH trial to investigate whether vitamin D supplementation would benefit patients aged 70 years or older with isolated systolic hypertension. According to the study background, previous observational studies have associated prevalent and incident hypertension and CVD with low levels of 25-hydroxyvitamin D, but no study had analyzed the effect of vitamin D supplementation on isolated systolic hypertension, the most common form of hypertension in older adults.
The researchers studied 159 patients (mean age, 77 years) with 25-hydroxyvitamin D levels <30 ng/mL, systolic BP >140 mm Hg and diastolic BP <90 mm Hg. One group was assigned a total 100,000 U oral cholecalciferol (Vigantol oil; Merck) every 3 months for 1 year. The other was assigned placebo every 3 months for 1 year.
At 1 year, the 25-hydroxyvitamin D levels increased in the treatment group as compared with the placebo group (+8 ng/mL; P<.001).
The primary outcome was change in BP. At baseline, mean office systolic BP was 163/78 mm Hg. At 3 months, there was no difference in mean BP between the vitamin D supplementation and placebo groups (–1 mm Hg; 95% CI, –6 mm Hg to 4 mm Hg vs. –2 mm Hg; 95% CI, –4 mm Hg to 1 mm Hg, respectively). The researchers also found no difference in overall treatment effect (1 mm Hg; 95% CI, –2 mm Hg to 4 mm Hg vs. 0 mm Hg; 95% CI, –2 mm Hg to 2 mm Hg).
Vitamin D supplementation had no significant treatment benefit over placebo for any of the secondary outcomes, including 24-hour BP, arterial stiffness, endothelial function, cholesterol levels, glucose levels and walking distance.
Both groups showed similar rates of adverse events, with no excess of adverse events in any subcategory. Total number of falls was lower in the group assigned vitamin D (36 vs. 46 falls; P=.24).
The researchers discussed several possible explanations for the results. For example, vitamin D may have no significant effect on BP overall or no significant effect on BP in this specific patient group, the dose studied may have been insufficient or incorrect, and other factors may be required for vitamin D to produce a beneficial effect on BP.
“It is still possible, however, that vitamin D supplementation could have beneficial effects on cardiovascular health via non-blood pressure effects, and ongoing large randomized trials are due to report on this in the next few years,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.