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Genetic Influences on Vitamin D Status and Forearm Fracture Risk in African American Children
  1. Leticia Manning Ryan, MD, MPH*†‡,
  2. James M. Chamberlain, MD*†,
  3. Steven A. Singer, MD§,
  4. Rachel Wood, BS,
  5. Laura L. Tosi, MD,
  6. Robert J. Freishtat, MD, MPH*‡,
  7. Heather Gordish-Dressman, PhD,
  8. Stephen J. Teach, MD, MPH*†,
  9. Joseph M. Devaney, PhD
  1. From the *Division of Emergency Medicine, †Center for Clinical and Community Research, Children’s National Medical Center, Washington, DC; ‡Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Research Center for Genetic Medicine, Children’s National Medical Center; §Department of Emergency Medicine, George Washington University Medical Center, Washington, DC; and ∥Division of Orthopaedics and Sports Medicine, Children’s National Medical Center, Washington, DC.
  1. Received January 24, 2012, and in revised form March 1, 2012.
  2. Accepted for publication March 9, 2012.
  3. Reprints: Leticia Manning Ryan, MD, MPH, Children’s National Medical Center, Division of Emergency Medicine, 111 Michigan Avenue, NW, Washington, DC 20010. E-mail: lryan{at}
  4. This study is funded in part by the National Institutes of Health National Center for Research Resources (1K23 RR024467-01).
  5. The authors have no conflicts of interest to disclose related to this article.
  6. Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal’s Web site (


We sought to investigate the relationship between newly identified genetic variants and vitamin D levels and fracture risk in healthy African American (black) children. This case-control study included children of both sexes, ages 5 to 9 years, with and without forearm fractures. Serum 25-hydroxy vitamin D levels, bone mineral density, body mass index, and calcium/vitamin D intake were measured in 130 individuals (n = 60 cases and n = 70 controls). The 5 variants tested were located in the GC gene (rs2282679), in the NADSYN1 gene (rs12785878 and rs3829251), and in the promoter region of the CYP2R1 gene (rs2060793 and rs104741657). Associations between single nucleotide polymorphisms (SNPs) and vitamin D levels were tested using an analysis of covariance. Associations between SNPs and fracture status were tested using logistic regression. The GC gene variant was associated with vitamin D levels (P = 0.038). None of the SNPs were associated with fracture status in young blacks. These results suggest that the variants tested, which are associated with circulating vitamin D levels in whites, are not associated with fracture status in healthy black children. Additional research is required to discover the genetics of fracture risk in blacks.

Key Words
  • fracture risk
  • single nucleotide polymorphism
  • vitamin D levels
  • body mass index
  • bone mineral density

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