Racial Difference in Response to Vitamin D Supplementation

This manuscript is the result of work supported by the use of resources and facilities at the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, specifically, the Geriatric Research Education and Clinical Center (GRECC).

Deficiency in 25-hydroxyvitamin D (25[OH]D) is common, especially in the elderly and African Americans (AA). While 25(OH) D deficiency is associated with multiple negative health outcomes, current recommendations for supplementation of this deficiency may be insufficient.

To determine the prevalence of 25(OH)D deficiency, the extent of vitamin D supplementation, and the effect of supplementation on 25(OH) D levels in an elderly Veteran population. The study also focused specifically on the role of race in the risk for 25(OH)D deficiency and in the response to vitamin D supplementation.

A retrospective chart review was conducted of information including 25(OH)D serum levels pre and post-supplementation, race, and vitamin D supplementation. Subjects were community-dwelling Veterans (≥60years) followed by a VA geriatric clinic. A total of 234 charts were reviewed (124 Caucasian, 78 AA, 32 other/unknown race). Information collected through the chart review was analyzed by comparing the means of 25(OH)D levels pre and post-supplementation across races and across times.

At Baseline 206 subjects (88%) were 25(OH)D deficient (<32ng/ml). While 80.6% of them were supplemented, only 10.24% (17 of 166) achieved normal 25(OH)D serum levels. AAs (n=78) had significantly lower Baseline levels compared to Caucasians (n=124) and differences were consistent across time. Fewer AAs than Caucasians increased to normal (AA:6.3%; Caucasian:12.8%).

Conservative oral vitamin D supplementation is largely ineffective at achieving therapeutic serum levels, especially for AAs. Future research is needed to focus on individualized supplementation strategies and targeted risk factors such as race.