Exercise and Health Laboratory, Faculty of Human Movement, Technical University of Lisbon, Lisbon, Portugal.
J Bone Miner Res. 2010 Nov;25(11):2304-12. doi: 10.1002/jbmr.229.
Bone strength is the result of its material composition and structural design, particularly bone mass distribution. The purpose of this study was to analyze femoral neck bone mass distribution by Ward's area location and its relationship with physical activity (PA) and body composition in children 8 and 9 years of age. The proximal femur shape was defined by geometric morphometric analysis in 88 participants (48 boys and 40 girls). Using dual-energy X-ray absorptiometry (DXA) images, 18 landmarks were digitized to define the proximal femur shape and to identify Ward's area position. Body weight, lean and fat mass, and bone mineral were assessed by DXA, PA by accelerometry, and bone age by the Tanner-Whitehouse III method. Warps analysis with Thin-Plate Spline software showed that the first axis explained 63% of proximal femur shape variation in boys and 58% in girls. Most of this variation was associated with differences in Ward's area location, from the central zone to the superior aspect of the femoral neck in both genders. Regression analysis demonstrated that body composition explained 4% to 7% of the proximal femur shape variation in girls. In boys, body composition variables explained a similar amount of variance, but moderate plus vigorous PA (MVPA) also accounted for 6% of proximal femur shape variation. In conclusion, proximal femur shape variation in children ages 8 and 9 was due mainly to differences in Ward's area position determined, in part, by body composition in both genders and by MVPA in boys. These variables were positively associated with a central Ward's area and thus with a more balanced femoral neck bone mass distribution.
骨强度是其物质组成和结构设计的结果，特别是骨量分布。本研究旨在通过 Ward 区位置分析 8 至 9 岁儿童股骨颈骨量分布及其与体力活动（PA）和身体成分的关系。在 88 名参与者（48 名男孩和 40 名女孩）中，通过几何形态测量分析定义了股骨近端的形状。使用双能 X 射线吸收法（DXA）图像，对 18 个标志点进行数字化处理，以定义股骨近端的形状并确定 Ward 区的位置。通过 DXA 评估体重、瘦体重和脂肪量以及骨矿物质，通过加速度计评估 PA，通过 Tanner-Whitehouse III 方法评估骨龄。薄板样条软件的扭曲分析表明，第一轴解释了男孩股骨近端形状变化的 63%，女孩为 58%。这种变化主要与 Ward 区位置的差异有关，在男女两性中，Ward 区从中心区到股骨颈的上侧。回归分析表明，身体成分解释了女孩股骨近端形状变化的 4%至 7%。在男孩中，身体成分变量解释了相似的方差量，但中等到剧烈的体力活动（MVPA）也占股骨近端形状变化的 6%。总之，8 至 9 岁儿童股骨近端形状的变化主要归因于 Ward 区位置的差异，在两性中部分取决于身体成分，在男孩中还取决于 MVPA。这些变量与中心 Ward 区呈正相关，从而与更平衡的股骨颈骨量分布相关。
