Endocrine Centre, Austin Health, the University of Melbourne, PO Box 5444, West Heidelberg, 3081 Melbourne, Australia.
Osteoporos Int. 2012 Feb;23(2):411-22. doi: 10.1007/s00198-011-1739-2. Epub 2011 Aug 19.
Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.
中国人的椎体骨折发生率相似，但髋部和前臂远端骨折的发生率低于白种人。造成骨骼脆弱的种族差异的潜在结构和生物力学基础在很大程度上仍未确定，但中国人的四肢骨骼较小，皮质和小梁较厚。不同种族的椎体骨折发生率相似，但髋部和前臂远端骨折的发生率低于白种人。这种种族差异不能用骨密度的差异来解释，因为中国人的骨密度较低主要是因为他们的体型较小。造成骨骼脆弱的种族差异的潜在结构和生物力学基础在很大程度上仍未确定，但中国人的四肢骨骼较小，其中的矿化骨基质较多；皮质较厚，可能孔隙较少，小梁较少但较厚且连接较多。这种结构使骨骼的表面积/体积比降低，从而减少了发生重塑的表面积，因此较低的表面积/体积比可能使骨骼较少受到重塑的影响，而较厚的皮质和小梁在发生重塑时也较少受到影响。然而，需要前瞻性研究来确定种族差异的发病年龄、皮质内、骨内膜和骨内膜内的骨丢失率、骨形成率；关于“骨丢失”的概念主要来源于横断面研究。需要研究骨形成和重塑的部位和表面特异性变化，以更好地定义老年人骨骼脆弱的种族差异。
