Vitamin D and BP in African Americans

A study titled “Effect of Vitamin D Supplementation on Blood Pressure in Blacks” has shown that vitamin D supplementation significantly yet modestly lowered systolic blood pressure in a group of African Americans.

In the study, 283 black patients with a median age of 51 were randomized into a 4-arm, double-blind trial for 3 months of placebo, 1000, 2000, or 4000 IUs of cholecalciferol per day.

The research took place during 2 winters from 2008 to 2010.

At baseline, 3 months, and 6 months, systolic and diastolic pressure and 25-hydroxyvitamin D were measured. The 3-month follow-up was completed in 250 participants (88%). The difference in systolic pressure between baseline and 3 months was +1.7 mm Hg for those receiving placebo, −0.66 mm Hg for 1000 U/d, −3.4 mm Hg for 2000 U/d, and −4.0 mm Hg for 4000 U/d of cholecalciferol (−1.4 mm Hg for each additional 1000 U/d of cholecalciferol; P=0.04).

For each 1-ng/mL increase in plasma 25-hydroxyvitamin D, there was a significant 0.2-mm Hg reduction in systolic pressure (P=0.02). There was no effect of cholecalciferol supplementation on diastolic pressure (P=0.37).

In an American Heart Association press release, the lead author of the study, John P. Forma, MD, MSc, commented, "Although this needs to be studied further, the greater prevalence of vitamin D deficiency among African-Americans may explain in part some of the racial disparity in blood pressure." Dr. Forman is an assistant professor of medicine in the Renal Division and Kidney Clinical Research Institute at Brigham and Women's Hospital in Boston, Mass. The study appeared in a recent issue of the journal Hypertension.