Low vitamin D linked with high blood pressure

NEW YORK (Reuters Health) - Lower blood levels of 25-hydroxyvitamin D, a protein that provides an acquire measure of vitamin D in the blood, are independently associated with an increased risk of developing high blood pressure, according to findings published in Hypertension.

Studies have shown 25(OH)D levels and skin exposure to UVB radiation...are associated with lower blood pressure, but definitive studies are limited, Dr. John P. Forman and colleagues from Brigham and Women's Hospital in Boston wrote.

The researchers conducted a study with1484 healthy women from the second Nurses' Health Study. Cases were compared with a placebo group with a similar age, race and other features. The subjects' average age was 43 years.

The case patients had a significantly lower average blood level of 25(OH)D than controls (25.6 ng/mL vs 27.3). Compared to women with the highest 25(OH)D levels, those with the lowest levels had a 66 percent increased risk of high blood pressure.

Overall, 65.7 percent of the women had vitamin D deficiency. In subjects who were vitamin D-deficient, the odds of developing high blood pressure were increased by 47 percent compared to those with adequate levels.

"Given that 65.7 percent of women were vitamin D deficient, the population risk attributable to vitamin D deficiency is 4.53 new cases of high blood pressure per 1000 young women annually," they note. "If this association is causal, then vitamin D deficiency may account for 23.7 percent of all new cases of high blood pressure developing among young women every year."

The authors call for randomized trials to determine whether vitamin D supplementation could reduce blood pressure.

SOURE: Hypertension, November 2008.