Lu P W, Cowell C T, LLoyd-Jones S A, Briody J N, Howman-Giles R
Robert Vines Growth Research Center, Royal Alexandria Hospital for Children, Sydney, Australia.
J Clin Endocrinol Metab. 1996 Apr;81(4):1586-90. doi: 10.1210/jcem.81.4.8636372.
Concerns have been raised regarding the validity of using areal bone mineral density (aBMD) as a substitute for the true volumetric bone mineral density (vBMD) in the pediatric population. We studied 209 normal subjects (109 males), aged 5-27 yr, to examine the influence of age, gender and growth on vBMD. The femoral neck, midthird of the femoral shaft, and the four lumbar vertebral bodies (L1-L4) were studied. Using data on bone width and height obtained by dual energy x-ray absorptiometry, bone volume was calculated with the assumption that all three sites are cylinders. In contrast to aBMD, vBMD of the femoral neck bore no relationship to age or weight in both sexes, but was significantly related to height in females (r2 = 0.07; P = 0.01). Similarly, vBMD of the femoral shaft (vFBMD) did not change with age or height in either sex. In females, a significant inverse relationship was seen between vFBMD and weight (r2 = 0.14; P = 0.001). Male subjects had higher vFBMD than females (mean +/- SD, 0.73 +/- 0.11 vs. 0.70 +/- 0.12; P = 0.047), but no sex difference was seen in vBMD of the femoral neck. Conversely, vBMD of L1-L4 remained age and growth dependent, although the strength of the relationship was weaker than that for aBMD (data not shown). In conclusion, the vBMD of the femoral neck and shaft is independent of age and is less dependent on growth variables in children and young adults than is aBMD. These observations offer a different perspective from our previous concepts of aBMD.
对于在儿科人群中使用面积骨密度（aBMD）替代真正的体积骨密度（vBMD）的有效性，人们已提出担忧。我们研究了209名年龄在5至27岁的正常受试者（109名男性），以考察年龄、性别和生长对vBMD的影响。研究部位包括股骨颈、股骨干中三分之一处以及四个腰椎椎体（L1 - L4）。利用双能X线吸收法获得的骨宽度和高度数据，假设所有三个部位均为圆柱体来计算骨体积。与aBMD不同，股骨颈的vBMD在两性中均与年龄或体重无关，但在女性中与身高显著相关（r2 = 0.07；P = 0.01）。同样，股骨干的vBMD（vFBMD）在两性中均不随年龄或身高变化。在女性中，vFBMD与体重之间存在显著的负相关（r2 = 0.14；P = 0.001）。男性受试者的vFBMD高于女性（均值±标准差，0.73±0.11 vs. 0.70±0.12；P = 0.047），但股骨颈的vBMD在两性中未见差异。相反，L1 - L4的vBMD仍依赖于年龄和生长，尽管这种关系的强度比aBMD弱（数据未显示）。总之，股骨颈和股骨干的vBMD与年龄无关，并且与儿童和青年成人的生长变量的相关性比aBMD小。这些观察结果与我们之前关于aBMD的概念提供了不同的视角。
