Division of Morphological Sciences and Biostatistics, Lifespan Health Research Center, Department of Community Health, Wright State University Boonshoft School of Medicine, USA.
Bone. 2012 Jul;51(1):38-45. doi: 10.1016/j.bone.2012.03.030. Epub 2012 Apr 5.
Elucidating the somatic and maturational influences on the biomechanical properties of bone in children is crucial for a proper understanding of bone strength and quality in childhood and later life, and has significant potential for predicting adult fracture and osteoporosis risks. The ability of a long bone to resist bending and torsion is primarily a function of its cross-sectional geometric properties, and is negatively impacted by smaller external bone diameter. In pubescent girls, elevated levels of estrogen impede subperiosteal bone growth and increase endosteal bone deposition, resulting in bones averaging a smaller external and internal diameter relative to boys. In addition, given a well-documented secular trend for an earlier menarche, the age at which the rate of subperiosteal bone deposition decreases may also be younger in more recent cohorts of girls. In this study we examined the relationship between pubertal timing and subsequent bone strength in girls. Specifically, we investigated the effects of age at menarche on bone strength indicators (polar moment of inertia and section modulus) determined from cross-sectional geometry of the second metacarpal (MC2) using data derived from serial hand-wrist radiographs of female participants (N=223) in the Fels Longitudinal Study, with repeated measures of MC2 between the ages of 7 and 35 years. Using multivariate regression models, we evaluated the effects of age at menarche on associations between measures of bone strength in early adulthood and the same measures at a prepubertal age. Results indicate that later age at menarche is associated with stronger adult bone (in torsion and bending) when controlling for prepubertal bone strength (R(2) ranged between 0.54 and 0.70, p<0.001). Since cross-sectional properties of bone in childhood may have long lasting implications, they should be considered along with pubertal timing in assessing risk for future fracture and in clinical recommendations.
阐明儿童骨骼生物力学特性的躯体和成熟影响因素对于正确理解儿童期和以后生活中的骨骼强度和质量至关重要，并且具有预测成人骨折和骨质疏松症风险的巨大潜力。长骨抵抗弯曲和扭转的能力主要是其横截面几何特性的函数，而较小的外部骨直径会对其产生负面影响。在青春期女孩中，雌激素水平升高会阻碍骨膜下骨生长并增加骨内骨沉积，导致与男孩相比，骨骼的外部和内部直径平均较小。此外，鉴于月经初潮较早的明显趋势，在最近几代女孩中，骨膜下骨沉积减少的年龄可能也会更早。在这项研究中，我们研究了青春期时间与女孩骨骼强度之间的关系。具体来说，我们研究了初潮年龄对第二掌骨（MC2）横截面几何形状确定的骨骼强度指标（极惯性矩和截面模数）的影响，这些数据来自女性参与者（N=223）的 Fels 纵向研究中的腕关节射线照片系列，在 7 至 35 岁之间对 MC2 进行了重复测量。使用多元回归模型，我们评估了初潮年龄对成年早期骨强度指标与青春期前骨强度指标之间的关联的影响。结果表明，在控制青春期前骨强度的情况下，初潮年龄较晚与成年骨骼（在扭转和弯曲时）更强相关（R(2) 介于 0.54 和 0.70 之间，p<0.001）。由于儿童骨骼的横截面特性可能具有长期影响，因此在评估未来骨折风险和临床建议时，应将其与青春期时间一起考虑。
