24,25-dihydroxyvitamin D3and vitamin D status of community-dwelling black and white Americans

Anders H. Berg, Camille E. Powe, Michele K. Evans, Julia Wenger, Guillermo Ortiz, Alan B. Zonderman, Pirianthini Suntharalingam, Kathryn Lucchesi, Neil R. Powe, S. Ananth Karumanchi, Ravi I. Thadhani

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: 24,25-Dihydroxyvitamin D [24,25(OH)2D] is a metabolite of 25-hydroxyvitamin D (25D). Blacks frequently have low total 25D without manifestations of vitamin D deficiency, suggesting that total serum 25D may incorrectly reflect vitamin D status in different racial groups. The ratio of serum 24,25(OH)2D to 25D [vitamin D metabolite ratio (VMR)] represents a new candidate biomarker for vitamin D status. METHODS: We measured 24,25(OH)2D3 and 25D3 by mass spectrometry in a random community cohort of black (n = 212) and white (n = 164) Americans to evaluate VMR as a marker for vitamin D status. We measured parathyroid hormone concentrations by immunoassay to compare VMR and 25D3 against a physiological indicator of vitamin D deficiency. RESULTS: Serum 24,25(OH)2D3 strongly correlated with 25D3 in both black and white study participants (r = 0.90, P < 0.001 and r = 0.86, P < 0.001 respectively). Blacks had lower mean 25D3 than whites [17.0 (7.8) vs 27.5 (11.3) ng/mL; 42.4 (19.5) vs 68.6 (28.2) nmol/L, P< 0.001] and lower mean 24,25(OH)2D3 [2.1 (1.3) vs 3.6 (2.0) ng/mL; 5.1 (3.1) vs 8.7 (4.8) nmol/L, P < 0.001]. In contrast to total 25D3 concentrations, mean VMR values were similar in blacks and whites [11.9 (4.0) vs 12.5 (3.4), P = 0.16, respectively] and were negatively correlated with parathyroid hormone concentrations in both races (rs = -0.26, P< 0.001, and rs = -0.25, P< 0.001, respectively). CONCLUSIONS: Our results provide further evidence that measurement of total 25D for assessment of vitamin D status in patients of African descent deserves reevaluation and suggest that alternative measures such as VMR should be considered.

Original languageEnglish (US)
Pages (from-to)877-884
Number of pages8
JournalClinical chemistry
Volume61
Issue number6
DOIs
StatePublished - Jun 1 2015

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, medical

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