Fiscella and Franks add to the increasing evidence that a low level of vitamin D is an independent risk factor for cardiovascular disease. And they show that the higher cardiovascular risk observed among blacks may be partly related to lower vitamin D levels, which the researchers point out are very prevalent among blacks because of lower absorption of vitamin D due to darker skin, lower dietary intake, and decreased sun exposure. Analyzing nationally representative data on more than 15,000 U.S. adults, researchers found that those with serum vitamin D, specifically 25 hydroxyvitamin D, or 25(OH)D, levels in the lowest quartile compared with those in the three higher quartiles had a 40 percent adjusted higher cardiovascular risk for death after accounting for other factors. Notably, they also found that the 38 percent higher cardiovascular mortality observed in blacks versus whites was attenuated by accounting for differences in 25(OH)D levels and fully eliminated with further adjustment for lower income. Specifically, they found that accounting for 25(OH)D levels reduced blacks’ higher risk of cardiovascular mortality by 60 percent, and inclusion of both 25(OH)D and poverty reduced the race risk to zero. The authors call for further research to determine whether vitamin D supplementation might improve cardiovascular outcomes and reduce existing racial health disparities.
Vitamin D, Race, and Cardiovascular Mortality: Findings From a National US Sample
By Kevin Fiscella, M.D., M.P.H., University of Rochester School of Medicine and Dentistry, New York, and Peter Franks, M.D., University of California, Davis
