Original Article

Osteoporosis International

, Volume 22, Issue 9, pp 2475-2485

First online:

The association of serum 25-hydroxyvitamin D with indicators of bone quality in men of Caucasian and African ancestry

  • K. E. BarbourAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of PittsburghCenter for Aging and Population Health Department of Epidemiology, University of Pittsburgh Email author 
  • , J. M. ZmudaAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of Pittsburgh
  • , M. J. HorwitzAffiliated withDivision of Endocrinology and Metabolism at the University of Pittsburgh School of Medicine
  • , E. S. StrotmeyerAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of Pittsburgh
  • , R. BoudreauAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of Pittsburgh
  • , R. W. EvansAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of Pittsburgh
  • , K. E. EnsrudAffiliated withMinneapolis VA Medical Center, Rheumatology (111 R)
  • , C. L. GordonAffiliated withDepartment of Radiology, McMaster University
  • , M. A. PetitAffiliated withSchool of Kinesiology, University of Minnesota
    • , A. L. PatrickAffiliated withTobago Health Studies Office
    • , J. A. CauleyAffiliated withDepartment of Epidemiology, Graduate School of Public Health, University of Pittsburgh
    • , Osteoporotic Fractures in Men (MrOS) Research Group

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Abstract

Summary

We examined the association of serum 25-hydroxyvitamin D [25(OH)D] with indices of bone quality in older men. Positive associations for 25(OH)D and bone mineral density, content, cortical thickness, and axial and polar strength strain indices were observed among Caucasians; however, among men of African descent findings were either null or negative.

Introduction

There are limited data on serum 25(OH)D and bone measures in men of African ancestry. To better understand racial differences in vitamin D status and bone health, a cross-sectional study among 446 Caucasian men in the US and 496 men of African ancestry in Tobago (age ≥ 65 years) was conducted.

Methods

Serum 25(OH)D (liquid chromatography and tandem mass spectrometry) was measured, and peripheral quantitative computed tomography scans were administered. Bone measures estimated included trabecular and cortical volumetric bone mineral density (vBMD), bone mineral content (BMC), bone geometry (cross-sectional area and cortical thickness), and polar and axial strength strain indices (SSIp and SSIx).

Results

Men of African ancestry had higher 25(OH)D than Caucasians (34.7 vs. 27.6 ng/ml, p < 0.01). Among Caucasians, 25(OH)D was positively (p trend < 0.05) associated with cortical vBMD, total BMC, cortical thickness, SSIp, and SSIx at the distal radius after adjustment for potential confounders. Similar patterns were observed at the distal tibia. In contrast, in men of African ancestry, there was an inverse association (p trend < 0.05) between 25(OH)D and the cross-sectional area, and SSIx. Race modified (p for interaction < 0.05) the association between 25(OH)D and total BMC, cross-sectional area, SSIp, SSIx, and trabecular vBMD of the radius. In men of African ancestry, there was evidence of a threshold effect (at approximately 18 ng/ml) for 25(OH)D on tibial total BMC and cortical thickness.

Conclusions

More studies are needed to better comprehend these race differences for 25(OH)D and bone density, geometry, and indices of bone strength.

Keywords

25(OH)D Men pQCT Radius Tibia vBMD