Jan. 7, 2010 -- African-Americans are more likely than whites to die of heart attacks, strokes, and other cardiovascular causes. Now intriguing new research suggests that low vitamin D levels may help explain this disparity.
Darker-skinned people produce less vitamin D from the sun than those with lighter skin, and studies show that blacks are far more likely to have lower levels of the vitamin than whites.
Several recent studies also suggest that low levels of vitamin D are associated with an increased risk for heart attack and stroke.
In an effort to examine the role of vitamin D in the racial disparity in cardiovascular death, researchers analyzed data from a national health and nutrition survey that included more than 15,000 people.
Vitamin D levels were measured at the time the survey was conducted, and the participants were followed for up to 12 years.
Compared to everyone else in the study, the quarter with the lowest vitamin D levels had a 40% higher risk of dying from heart attacks, strokes, and other heart-related events.
Blacks were 38% more likely to die of cardiovascular causes than non-Hispanic whites, and the researchers concluded that most of this excess was related to their lower vitamin D levels.
The findings suggest, but do not prove, that low vitamin D raises cardiovascular risk, says study researcher Kevin Fiscella, MD, MPH, of the University of Rochester School of Medicine and Dentistry.
Fiscella and co-researcher Peter Franks, MD, of the University of California at Davis, published their study in the January/February issue of the Annals of Family Medicine.
"The message is that vitamin D deficiency might be a major contributor to cardiovascular deaths," he tells WebMD. "We really need clinical trials to understand this association."
Fiscella points out that vitamin C, vitamin E, and beta-carotene were all thought to lower heart attack and stroke risk just a few years ago. But the early excitement was not borne out in clinical trials.