Bone Mineral Accretion in Young Children

项目摘要患有慢性疾病的儿童面临骨骼强度受损的风险 并增加了骨折易感性。最近开发的参考数据使临床医生能够识别 5至20岁骨矿物质状况受损(年龄骨密度低)的儿童，并优化他们的医疗 关心。一个明显的缺陷是无法评估幼儿的骨健康状况，因为缺乏适当的 骨密度参考数据，尽管有许多临床情况(例如，早产、胃肠道和 神经肌肉疾病)威胁着这一年龄段的骨骼健康。 幼儿期与其他发展阶段不同。在年龄较大的儿童中，需要考虑到成长 在解释骨骼测量时的状态和瘦肉质量已经被证明，但在儿童早期， 这些影响是未知的。在粗大运动技能、运动和体力活动方面也有显著变化 发生在儿童早期。骨骼生长过程中的机械负荷会促进骨矿物质的积累。 了解生长、身体成分、运动技能发展和体力活动对骨骼的影响 幼儿的骨矿含量对于临床骨矿物质状态测量的解释至关重要。这些 患有慢性疾病的幼儿的性格特征往往会受到影响。 这项研究的长期目标是优化幼儿的骨骼健康。这样做的目的是 纵向研究是发展局部和全身的骨矿含量(Bmc)和密度(ABMD)。 1-5岁儿童的参考数据，以帮助识别有骨缺陷的幼儿，并确定 影响这一年龄段骨积量的因素。这项纵向研究的目的是：(1)性别测试 1至5岁健康儿童多个骨骼部位的BMC和aBMD的祖先差异 创建适当的参考曲线；(2)评估生长和身体成分的影响；以及(3)粗略 运动技能和体力活动对骨矿物质状态和骨矿物质积累的影响，以及(4)决定 幼儿骨骼状况的“追踪”程度。有待检验的假设是：男性将拥有更大的 BMC和aBMD高于女性；黑人将比非黑人有更大的BMC和aBMD；骨矿状况 生长状况越好、瘦组织越多、进展期越晚的儿童，骨积累越大 粗大的运动技能和较高的体力活动水平；以及BMC和aBMD z分数将呈正相关 3岁以上。这项研究是独一无二的，因为以前没有研究涉及1-5岁儿童的这些问题。它是 具有临床相关性，因为研究结果将有助于患有慢性疾病的儿童的医疗护理 威胁骨骼健康，并将开发和验证骨骼和身体成分的新方法 在这个年龄段进行评估。它还将增加概括性知识，以增强对 骨骼生长及其与运动和躯体发育的关系。由于不良的骨矿物质积累可以 具有终生后果，这项研究解决了骨质疏松症这一主要的公共卫生问题。

PROJECT SUMMARY Children with chronic medical conditions are at risk of compromised bone strength and increased fracture susceptibility. Recently developed reference data have enabled clinicians to identify children 5 to 20 y with compromised bone mineral status (low bone density for age) and optimize their medical care. A glaring deficit is the inability to evaluate bone health of young children < 5 y due to lack of appropriate bone density reference data, although numerous clinical conditions (e.g., prematurity, gastrointestinal and neuromuscular disorders) threaten bone health in this young age range. Early childhood differs from other developmental stages. In older children, the need to account for growth status and lean mass when interpreting bone measurements has been demonstrated, but in early childhood, these effects are unknown. Pronounced changes in gross motor skills, locomotion and physical activity also occur in early childhood. Mechanical loads on the growing skeleton promote bone mineral accrual. Understanding the impact of growth, body composition, motor skill development, and physical activity on bone accrual in young children is critical for interpretation of a clinical bone mineral status measurement. These characteristics are often affected in young children with chronic medical conditions. The long-term goal of this study is to optimize bone health of young children. The objectives of this longitudinal study are to develop regional and total body bone mineral content (BMC) and density (aBMD) reference data for children ages 1-5 y to aid identification of young children with bone deficits, and identify factors that influence bone accrual in this age group. The aims of this longitudinal study are: (1) test for sex and ancestry differences in BMC and aBMD at multiple skeletal sites in healthy children ages 1 to 5 y, and create appropriate reference curves; (2) assess the influence of growth and body composition, and (3) gross motor skills and physical activity on bone mineral status and bone mineral accrual, and (4) determine the degree of "tracking" of bone status in young children. Hypotheses to be tested are: males will have greater BMC and aBMD than females; Blacks will have greater BMC and aBMD than non-blacks; bone mineral status and bone accrual will be greater in children with greater growth status and more lean tissue, more advanced gross motor skills, and higher physical activity levels; and BMC and aBMD z-scores will be positively correlated over 3 y. The study is unique since no previous studies have addressed these issues in children 1-5 y. It is clinically relevant as findings will facilitate medical care of children with chronic medical conditions that threaten bone health, and it will develop and validate novel methods for bone and body composition assessment in this age range. It will also add generalizable knowledge to enhance understanding of the growing skeleton, and its relationship to motor and somatic development. Since poor bone mineral accrual can have lifelong consequences, this study addresses the major public health concern of osteoporosis.