Bone Mineral Accretion in Young Children

患有慢性疾病的儿童有骨强度受损的风险 和增加的断裂敏感性。最近开发的参考数据使临床医生能够识别 5 - 20岁骨矿物质状况受损（骨密度低于年龄）的儿童，并优化他们的医疗 在乎一个明显的缺陷是，由于缺乏适当的评估，无法评估5岁以下幼儿的骨骼健康。 骨密度参考数据，尽管许多临床状况（例如，早产、胃肠道和 神经肌肉疾病）威胁着这个年轻年龄段的骨骼健康。 幼儿期不同于其他发育阶段。在年龄较大的儿童中， 状态和瘦体重时，解释骨骼测量已被证明，但在幼儿期， 这些影响是未知的。大运动技能、运动和身体活动也发生明显变化 发生在儿童早期。机械负荷对骨骼生长促进骨矿物质积累。 了解生长、身体成分、运动技能发展和身体活动对骨骼的影响 在幼儿中的增加对于解释临床骨矿物质状态测量是至关重要的。这些 患有慢性疾病的幼儿的特征往往受到影响。 这项研究的长期目标是优化幼儿的骨骼健康。这一目标 纵向研究是发展区域和全身骨矿物质含量（BMC）和密度（aBMD） 1-5岁儿童的参考数据，以帮助识别骨缺损的幼儿，并确定 影响该年龄组骨增长的因素。本纵向研究的目的是：（1）性别测试 1 - 5岁健康儿童多个骨骼部位BMC和aBMD的血统差异，以及 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）总体 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）确定 幼儿骨骼状况的“跟踪”程度。待检验的假设是：男性将拥有更大的 BMC和aBMD高于女性;黑人的BMC和aBMD高于非黑人;骨矿物质状态 在生长状态更好、瘦肉组织更多、更先进的儿童中， 粗大运动技能和更高的体力活动水平; BMC和aBMD z评分呈正相关 超过3年。这项研究是独一无二的，因为以前没有研究解决这些问题的儿童1-5岁。是 具有临床意义的发现将有助于对患有慢性疾病的儿童进行医疗护理， 威胁骨骼健康，并将开发和验证骨骼和身体组成的新方法 在这个年龄段进行评估。它还将增加可推广的知识，以加强对 生长的骨骼，以及它与运动和躯体发育的关系。由于骨矿物质积累不足， 有终身的后果，这项研究解决了骨质疏松症的主要公共卫生问题。

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.