Dr. Kevin Fiscella of the University of Rochester School of Medicine and Dentistry and Dr. Peter Franks of the University of California, Davis, showed the higher cardiovascular risk observed among blacks may be partly related to lower vitamin D levels. The researchers point out blacks have lower vitamin D levels because of lower absorption of vitamin D due to darker skin, lower dietary intake and decreased sun exposure.
The researchers analyzed nationally representative data on more than 15,000 U.S. adults and found those with serum vitamin D levels in the lowest quartile, specifically 25 hydroxyvitamin D, compared with those in the three higher quartiles had a 40 percent adjusted higher cardiovascular risk for death after accounting for other factors.
The researchers found the 38 percent higher cardiovascular mortality observed in blacks vs. whites was attenuated by accounting for differences in 25(OH)D levels and fully eliminated with further adjustment for lower income.
Fiscella and Franks 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.
The findings are published in the Annals of Family Medicine.