Better skeletal microstructure confers greater mechanical advantages in Chinese-American women versus white women

Authors

  • X Sherry Liu,

    1. Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • Marcella D Walker,

    1. Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • Donald J McMahon,

    1. Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • Julia Udesky,

    1. Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • George Liu,

    1. New York Downtown Hospital, Department of Medicine, New York, NY, USA
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  • John P Bilezikian,

    1. Department of Medicine, Division of Endocrinology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • X Edward Guo

    Corresponding author
    1. Bone Bioengineering Laboratory, Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
    • Bone Bioengineering Laboratory, Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, New York, NY 10027, USA.
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Abstract

Despite lower areal bone mineral density (aBMD), Chinese-American women have fewer fractures than white women. We hypothesized that better skeletal microstructure in Chinese-American women in part could account for this paradox. Individual trabecula segmentation (ITS), a novel image-analysis technique, and micro–finite-element analysis (µFEA) were applied to high-resolution peripheral quantitative computed tomography (HR-pQCT) images to determine bone microarchitecture and strength in premenopausal Chinese-American and white women. Chinese-American women had 95% and 80% higher plate bone volume fraction at the distal radius and tibia, respectively, as well as 20% and 18% higher plate number density compared with white women (p < .001). With similar rodlike characteristics, the plate-to-rod ratio was twice as high in the Chinese-American than in white trabecular bone (p < .001). Plate-rod junction density, a parameter indicating trabecular network connections, was 37% and 29% greater at the distal radius and tibia, respectively, in Chinese-American women (p < .002). Moreover, the orientation of the trabecular bone network was more axially aligned in Chinese-American women because axial bone volume fraction was 51% and 32% higher at the distal radius and tibia, respectively, than in white women (p < .001). These striking differences in trabecular bone microstructure translated into 55% to 68% (distal radius, p < .001) and 29% to 43% (distal tibia, p < .01) greater trabecular bone strength, as assessed by Young's moduli, in the Chinese-American versus the white group. The observation that Chinese-American women have a major microstructural advantage over white women may help to explain why their risk of fracture is lower despite their lower BMD. © 2011 American Society for Bone and Mineral Research

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