Cardadeiro G, Baptista F, Rosati N, Zymbal V, Janz K F, Sardinha L B
Exercise and Health Laboratory, Interdisciplinary Centre for the Study of Human Performance, Faculty of Human Kinetics, University of Lisbon, Lisbon, Portugal.
Osteoporos Int. 2014 Aug;25(8):2035-45. doi: 10.1007/s00198-014-2729-y. Epub 2014 May 9.
Physical activity (PA) have long been identified as a determining factor of the mineralization of the skeleton, particularly in children. Our research supports the hypothesis that the geometry of the pelvis and proximal femur (PF) might moderate the effect of PA in the relative mineralization of the PF subregions.
Using a longitudinal observational study with two evaluations and a 1-year follow-up interval, we investigated the influence of PA and skeletal geometry in bone mineral density (BMD) and bone mass distribution at the PF in 96 girls and 81 boys (10-12 years). It is plausible that the geometry of the pelvis-PF structure moderates mechanical forces exerted at the hip and therefore creates different degrees of mineralization among PF subregions.
Whole body and left hip dual X-ray absorptiometry scans were used to derive geometric measures of the pelvis-inter-acetabular distance (IAD) and PF abductor lever arm (ALA). BMD was measured at the integral, superolateral (SL), and inferomedial (IM) femoral neck (FN), and at the trochanter (TR). These subregions were used to represent bone mass distribution via three BMD ratios: FN/PF, IM/SL, and TR/PF. PA was measured using accelerometry and a bone-specific PA questionnaire (BPAQ).
A longitudinal data approach revealed BPAQ as a positive predictor for all BMD variables (p < 0.05) except TR BMD in girls and FN BMD in boys. Comparing the most active with the less-active participants, the greatest benefits of PA were observed at the FN of the girls with the lowest IAD (p < 0.001), at the FN of the boys with the highest IAD (p < 0.001) and at the TR of the boys with the lowest ALA (p < 0.01).
Geometric measures of IAD and ALA seem to moderate the effect of PA role in the relative mineralization of the PF regions. On the other hand, absolute BMD levels appear to be determined by mechanical loading.
长期以来，身体活动（PA）一直被认为是骨骼矿化的一个决定性因素，尤其是在儿童中。我们的研究支持这样一种假设，即骨盆和股骨近端（PF）的几何形状可能会调节PA对PF各亚区域相对矿化的影响。
通过一项有两次评估且随访间隔为1年的纵向观察性研究，我们调查了PA和骨骼几何形状对96名女孩和81名男孩（10 - 12岁）PF处骨密度（BMD）和骨量分布的影响。骨盆 - PF结构的几何形状调节施加在髋部的机械力，从而在PF各亚区域产生不同程度的矿化，这是合理的。
使用全身和左髋双能X线吸收法扫描来获取骨盆的几何测量值——髋臼间距离（IAD）和PF外展肌杠杆臂（ALA）。在股骨颈（FN）的整体、上外侧（SL）和下内侧（IM）以及转子（TR）处测量BMD。这些亚区域通过三个BMD比值来表示骨量分布：FN/PF、IM/SL和TR/PF。使用加速度计和一份骨骼特异性PA问卷（BPAQ）来测量PA。
纵向数据方法显示，BPAQ是除女孩的TR BMD和男孩的FN BMD之外所有BMD变量的正向预测因子（p < 0.05）。将最活跃的参与者与较不活跃的参与者进行比较，在IAD最低的女孩的FN处（p < 0.001）、IAD最高的男孩的FN处（p < 0.001）以及ALA最低的男孩的TR处（p < 0.01）观察到PA的最大益处。
IAD和ALA的几何测量值似乎会调节PA在PF区域相对矿化中的作用。另一方面，绝对BMD水平似乎由机械负荷决定。
