Exercise and Bone Development in Young Girls

年轻女孩的运动和骨骼发育

• 批准号: 7799754
• 负责人: Scott B Going
• 金额: $ 63.87万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-11 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7799754
• 关键词: Acceleration; Address; Adolescence; Adolescent; Adult; Age; Animals; Area; Attention; Body Composition; Body Size; Bone Density; Bone Development; Bone Mineral Contents; Boxing; Child; Childhood; Conflict (Psychology); Cross-Sectional Studies; Data; Development; Diet; Disease; Dose; Dual-Energy X-Ray Absorptiometry; Environment; Environmental Risk Factor; Exercise; Fostering; Fracture; Future; Growth; Health; Humulus; Incidence; Intervention; Investigation; Length; Life; Life Style; Longevity; Maintenance; Measurement; Measures; Mechanics; Methods; Minerals; Osteoporosis; Osteoporosis prevention; Participant; Physical activity; Prevention; Public Health; Publishing; Reaction; Relative (related person); Reporting; Research Personnel; Risk; Sampling; Shapes; Site; Staging; Stimulus; Structure; Testing; Thick; Time; Weight-Bearing state; Work; Writing; Youth; base; bone; bone loss; bone mass; bone strength; clinically significant; control trial; density; design; follow-up; girls; improved; interest; intervention effect; osteogenic; pediatrician; post intervention; programs; prospective; response; skeletal; therapy design; two-dimensional

DESCRIPTION (provided by applicant): Osteoporosis, with its increased fracture risk, is a major public health concern. While the majority of past prevention efforts have targeted slowing bone loss, there is great interest in skeletal adaptations to interventions during development. Both bone mass and structural geometry are important determinants of bone strength and fracture risk. Animal studies clearly show structural adaptations to mechanical stimuli during development. Children and adolescents, more so than adults, may have the ability to modify structural geometry as well as increase bone mineral mass and density in response to increased loads, which would increase bone strength and potentially protect against fractures later in life. This proposition has not been adequately tested. Moreover, from the few available studies, there have been conflicting reports regarding relative adaptations in girls at different stages of development. Thus the optimal timing of interventions is not known. To address these issues, we propose to assess the effects of "ground-reaction (e.g., jumping, hopping, etc.) exercise on bone macro-architectural development in pre-pubescent and early pubescent girls. Bone mineral content (BMC), bone mineral density (BMD), and bone structural geometry will be measured in girls in 4th (Tanner stage 1) and 6th (Tanner stage II and III) grade at baseline, and at regular intervals thereafter, to assess the effects of two years of exercise on bone accrual and structure. Follow-up measures will be made at 1 and 2 years post intervention to assess whether intervention effects persist. Physical activity, diet, maturation, body size and body composition will also be measured to control for differences in growth, maturation, and important environmental factors that may influence bone development and the interpretation of the adaptations to the intervention. This study is unique in several ways including: i) its focus on structural changes in addition to BMC and BMD; ii) the focus on pre- and early pubescent girls to define the optimal "window of opportunity" for adaptation to occur; iii) the two-year intervention so we can examine whether benefits continue to accrue with longer duration intervention; iv) comprehensive measurement of important covariates; and v) its focus on the maintenance of adaptations over two years of follow-up after intervention. Past studies have failed to adequately control for body and bone size, which confound area) BMD from DXA, and which vary with maturation. The inclusion of pQCT vBMD and measures of structural geometry allows an appropriate interpretation of changes in BMC and BMD, and provides a prospective test of the effects of exercise on structural adaptations in developing girls which contribute to bone strength and which may have lasting benefit for lowering fracture risk. We expect this study will make a significant contribution to our understanding of bone macro-architectural adaptations to exercise and will provide critical information for the design and optimal timing of interventions designed to enhance bone development to lessen future fracture risk.

描述（由申请人提供）：骨质疏松症及其增加的骨折风险是一个主要的公共卫生问题。虽然过去大多数预防工作的目标都是减缓骨质流失，但人们对骨骼对发育过程中干预措施的适应非常感兴趣。骨量和结构几何形状都是骨强度和骨折风险的重要决定因素。动物研究清楚地表明发育过程中对机械刺激的结构适应。儿童和青少年比成人更有能力改变结构几何形状以及增加骨矿物质质量和密度以应对增加的负荷，这将增加骨强度并可能在以后的生活中预防骨折。这个提议还没有经过充分的测试。此外，从现有的几项研究来看，关于不同发育阶段女孩的相对适应情况存在相互矛盾的报告。因此，干预的最佳时机尚不清楚。为了解决这些问题，我们建议评估“地面反应（例如跳跃、跳跃等）运动对青春期前和青春期早期女孩骨骼宏观结构发育的影响。将在基线时测量四年级（坦纳 1 期）和六年级（坦纳 II 期和 III 期）女孩的骨矿物质含量 (BMC)、骨矿物质密度 (BMD) 和骨结构几何形状，并 此后定期评估两年锻炼对骨生成和结构的影响。干预后1年和2年将采取后续措施，以评估干预效果是否持续。还将测量体力活动、饮食、成熟度、体型和身体成分，以控制生长、成熟度和可能影响骨骼发育的重要环境因素的差异，并解释对干预措施的适应。这项研究在几个方面都是独一无二的，包括：i) 其重点 除了BMC和BMD之外的结构变化； ii) 重点关注青春期前和青春期早期的女孩，以确定适应发生的最佳“机会之窗”； iii) 为期两年的干预，以便我们可以检查长期干预是否会继续带来益处； iv) 重要协变量的综合测量； v) 其重点是在干预后两年的随访中维持适应性。过去的研究未能 充分控制身体和骨骼的大小，这与 DXA 的 BMD 相混淆，并且随着成熟度的变化而变化。 pQCT vBMD 和结构几何测量的纳入可以对 BMC 和 BMD 的变化进行适当的解释，并提供了运动对发育中女孩结构适应影响的前瞻性测试，这有助于骨强度，并可能对降低骨折风险具有持久益处。我们预计这项研究将产生重大影响 有助于我们理解骨骼宏观结构对运动的适应，并将为旨在增强骨骼发育以减少未来骨折风险的干预措施的设计和最佳时机提供关键信息。