BUILDING BETTER BONES IN CHILDREN

增加钙的摄入量已被证明对增加儿童的骨密度有效，但当停止补充钙时，这种效果就会消失。从日常和其他食物来源增加膳食钙可能对骨密度的影响甚至比钙补充剂更大，但从食物来源获得持续增加的钙尚未得到证实。此外，钙摄入量和骨密度的基线特征以及青春期状态的影响可能会影响对干预的反应。本研究将制定和实施一项行为改变-营养教育（BM-NE）干预计划，旨在增加膳食钙，男性和女性受试者（n=154），年龄7-10岁（坦纳I期或II期），将被随机分配至强化BM-NE干预组（将摄入量增加至1500 mg/d）或接受常规护理（UC）的组作为骨骼健康的咨询BM-NE计划将包括五个独立的小组会议，家长和孩子在五到六周的时间，并使用个性化的计划，以增加钙的摄入量。参与者将被招募成两组：一组健康儿童（即，无已知的慢性疾病或既往口服类固醇暴露），无已知的风险因素，以及一组健康儿童，具有低骨密度的潜在风险因素（既往因儿童期日常活动、每日拒绝或乳糖不耐受而骨折，骨质疏松症家族史）。这两个组在分配到BM-NE和UC组时的代表性相等。后一种策略将用于确定风险因素的存在是否会影响参与者对计划的依从性。我们假设：（a）在36个月结束时，与接受UC的患者相比，无风险BM-NE组的膳食钙至少增加300 mg/d，（B）基线钙摄入量和风险因素的存在将与研究过程中钙摄入量的变化相关，以及（c）在控制了重要的协变量如体型和性及骨骼成熟的增加后，BMD的变化将与钙摄入和体力活动相关。这些发现将有助于确定重要的行为策略，以增加峰值骨量和预防骨质疏松症，这些策略可以在短时间内实施，并产生持久的影响。此外，它将有助于量化增加膳食钙对生长和发育期间骨密度的影响，并可能确定最需要和对这种治疗有反应的儿童的特征。

Increased calcium intake has proven effective in increasing bone mineral density in children, but the effect disappears when calcium supplements are discontinued. Increased dietary calcium from daily and other food sources may have an even greater impact on bone density than that achieved by calcium supplements, but achieving sustained increased calcium from food sources has not been demonstrated. In addition, the effects of baseline characteristics of calcium intake and bone density and puberty status may influence the response to intervention. This study will develop and implement a Behavioral Modification-Nutrition Education (BM-NE) Intervention Program aimed at increasing dietary calcium Male and female subjects (n=154), ages 7-10 years (Tanner stage I or II), will be randomly assigned to participate in an intensive BM-NE intervention group to increase intake to 1500 mg/d or a group that will receive usual care (UC) as counseling on bone health. The BM-NE Program will consist of five separate group sessions for parents and children over a five to six week period, and use individualized plans to increase calcium intake. Participants will be recruited into two groups: a group of healthy children (i.e.,no known chronic disease or previous oral steroid exposure) with no known risk factors, and a group of healthy children with potential risk factors for low bone density (previous fracture from usual childhood activities, daily refusal, or lactose intolerance, family history of osteoporosis). These two groups will be equally represented in their assignment to BM-NE and UC groups. This latter strategy will be used to determine whether the presence of risk factors influences participant compliance with the programs. We hypothesize that (a) at the end of 36 months the BM-NE group will have increased dietary calcium of at least 300 mg/d in the no-risk BM-NE group compared to those receiving UC, (b) baseline calcium intake and presence of risk factors will be associated with changes in calcium intake over the course of the study, and (c) after controlling for important co-variates such as increases in body size and sexual and skeletal maturation, changes in BMD will be associated with calcium intake and physical activity. These findings will help define important behavioral strategies for increasing peak bone mass and prevention of osteoporosis later in life that can be implemented in a short period of time with long-lasting effects. Furthermore, it will help quantify the impact of increased dietary calcium on bone density during growth and development with possible identification of the characteristics of children most in need of and responsive to this treatment.