Vitamin D, race, and cardiovascular mortality: findings from a national US sample.
OBJECTIVE
Findings are conflicting about the relationship between vitamin D levels and cardiovascular mortality. We wanted to determine the contribution of vitamin D levels to black-white disparities in cardiovascular mortality.


METHODS
We examined the association of serum 25(OH)D levels with cardiovascular mortality and its contribution to elevated risk among blacks through a retrospective cohort using baseline data from the third National Health and Nutrition Examination Survey 1988-1994 and cause-specific mortality through 2001 using the National Death Index. Using piecewise Poisson regression models, we examined the risk of cardiovascular death (coronary heart disease, heart failure, and stroke) by sample 25(OH)D quartile, adjusting for cardiovascular risk factors, and compared models of adjusted race-related cardiovascular mortality with and without further adjustment for 25(OH)D levels.


RESULTS
Participants with 25(OH)D levels in the lowest quartile (mean = 13.9 ng/mL) compared with those in the 3 higher quartiles (mean = 21.6, 28.4, and 41.6 ng/mL) had higher adjusted risk of cardiovascular death (incident rate ratio [IRR] = 1.40; 95% confidence interval [CI], 1.16-1.70). The higher age- and sex-adjusted cardiovascular mortality observed in blacks vs whites (IRR = 1.38; 95% CI, 1.13-1.70) was attenuated (IRR = 1.14; 95% CI, 0.91-1.44) by adjustment for 25(OH)D levels and fully eliminated with further adjustment for income (IRR=1.01; 95% CI, 0.82-1.24).


CONCLUSIONS
Low serum levels of 25(OH)D are associated with increased cardiovascular mortality in a nationally representative US sample. Black-white differences in 25(OH)D levels may contribute to excess cardiovascular mortality in blacks. Interventional trials among persons with low vitamin D levels are needed to determine whether oral supplementation improves cardiovascular outcomes.
Fiscella
Kevin
K
Department of Family Medicine and Department of Community & Preventive Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA. Kevin_Fiscella@URMC.rochester.edu
Franks
Peter
P
D000328:Adult; D044383:Black People; D002318:Cardiovascular Diseases / Q000150:complications / Q000208:ethnology* / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood / Q000172:deficiency*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016017:Odds Ratio; D013308:Streptonigrin; D014481:United States / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000208:ethnology*; D044465:White People; D001741:Black or African American
D006887:Hydroxycholecalciferols; C079133:retrostatin; D013308:Streptonigrin