A Prospective Study of Serum 25-Hydroxyvitamin D Levels and Mortality Among African Americans and Non-African Americans

The beneficial biologic effects attributed to vitamin D suggest a potential to influence overall mortality. Evidence addressing this hypothesis is limited, especially for African Americans who have a high prevalence of vitamin D insufficiency. The authors conducted a nested case-control study within the prospective Southern Community Cohort Study to relate baseline serum levels of 25-hydroxyvitamin D (25(OH)D) with subsequent mortality. Cases were 1,852 participants who enrolled from 2002 to 2009 and died 12 months postenrollment. Controls (n 1,852) were matched on race, sex, age, enrollment site, and blood collection date. The odds ratios for quartile 1 (10.18 ng/mL) versus quartile 4 (21.64 ng/mL) levels of 25(OH)D were 1.60 (95 confidence interval (CI): 1.20, 2.14) for African Americans and 2.11 (95 CI: 1.39, 3.21) for non-African Americans. The effects were strongest for circulatory disease death, where quartile 1 versus quartile 4 odds ratios were 2.53 (95 CI: 1.44, 4.46) and 3.25 (95 CI: 1.33, 7.93) for African Americans and non-African Americans, respectively. The estimated odds of total mortality were minimized in the 25(OH)D range of 3540 ng/mL. These findings provide support for the hypothesis that vitamin D status may have an important influence on mortality for both African Americans and non-African Americans.