There is no way of knowing whether increased vitamin D intake over the years might have affected the incidence of high blood pressure, a major risk factor for such cardiovascular problems as heart attack and stroke, Griffin said.
"This study underscores a growing amount of accumulated data that low vitamin D levels are associated with high blood pressure," said Dr. John P. Forman, an associate physician in the renal division of Brigham and Women's Hospital.
But it's still not certain that raising vitamin D intake can help prevent high blood pressure, Forman added. "We need large randomized trials on that," he said.
Still, he noted, "there are a growing number of studies associating lower vitamin D levels and high blood pressure. This one probably has the longest follow-up."
Known risk factors for high blood pressure are listed by the U.S. National Heart, Lung, and Blood Institute.
SOURCES: Flojaune C. Griffin, MPH, doctoral candidate, University of Michigan School of Public Health, Ann Arbor; John P. Forman, M.D., professor, medicine, Harvard Medical School, and associate physician, renal division, Beth Israel Deaconess Hospital, Boston; Sept. 24, 2009, presentation, American Heart Association High Blood Pressure Research Conference, Chicago
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