Lower cortical porosity and higher tissue mineral density in Chinese-American versus white women

Journal of Bone and Mineral Research, 08/02/2013

Boutroy S et al. – Asian women have lower rates of hip and forearm fractures compared to other racial groups despite lower areal BMD. The authors have demonstrated microarchitectural differences, including greater cortical thickness (Ct.Th) and cortical volumetric BMD (Ct.BMD), in Chinese–American versus white women. Yet, it is not known whether greater Ct.BMD in Chinese–American women is due to greater tissue mineral density (TMD) or reduced cortical porosity (Ct.Po). Both reduced Ct.Po and greater Ct.TMD explain higher Ct.BMD in Chinese–American versus white women. Thicker and preserved cortical bone structure in Chinese–American women may contribute to greater resistance to fracture compared to white women.

Methods

  • Using an advanced segmentation algorithm based on high-resolution peripheral quantitative computed tomography images, they tested the hypothesis that Chinese-American women have better cortical skeletal integrity due to lower Ct.Po and higher Ct.TMD compared with white women.
  • 78 Chinese-American women (49 pre- and 29 postmenopausal) and 114 white women (46 pre- and 68 postmenopausal) were studied.

Results

  • Premenopausal Chinese-American vs. white women had greater Ct.Th, Ct.BMD and Ct.TMD at both the radius and tibia; and decreased Ct.Po (p < 0.05).
  • A similar pattern was observed between postmenopausal Chinese-American and white women.
  • As expected, postmenopausal versus premenopausal women had lower Ct.BMD at the radius and tibia in both races (p < 0.001). Ct.Po largely increased between pre- and post-menopausal women, while Ct.TMD decreased by 3–8% (p < 0.001) in both races.
  • Age-related differences in Ct.Po and Ct.TMD did not differ by race.

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