LIFESTYLE CHANGE TO INCREASE BONE DENSITY IN TEEN GIRLS

在美国，与骨质疏松相关的骨折每年的成本为80亿美元，其中大部分由女性承担，尽管对可能改善绝经后骨密度下降(BMD)的因素进行了大量研究。终身预防战略的一个重要组成部分将是为14-20岁的年轻妇女创造方法，以最大限度地提高她们的骨矿含量，并将其保持到更年期。这项提案将严格测试两种综合生活方式干预措施，这两种干预措施都以健康饮食和可持续运动为导向，一种基于个人咨询，另一种基于集体干预，与注意力控制相对照。其目的是在征兵时在14岁至16岁的年轻女性中建立骨骼并防止骨质流失。这项试验借鉴了我们在两项关于青少年和营养的重要研究中的经验--青少年生活方式项目，DISC--以及正在进行的水果和蔬菜研究，DASH。该设计为平行组随机临床试验。300名参与者在两组中平均分配，并在基线和三次随访至27个月时进行测量。这将提供0.90的功率来检测L在组间TBBMD变化率的差异%-2%。二级分析将通过客观指标(血清叶酸和类胡萝卜素尿钠、瘦体重、体力活动加速计测量)以及自我报告，将饮食和锻炼目标的实现与对照组进行比较。第三次分析将检查两个干预组之间相同的饮食和运动结果。也涉及过程措施(遵守、评价、保留)。最终的分析将探索潜在的导致骨矿物质健康的途径，涉及更广泛的因素，如家族史、生物和行为因素、激素影响和骨代谢标记物。调查人员在行为矫正、对少女的研究、营养和运动干预方面拥有大量专业知识。他们在评估骨矿物质、身体力量、运动模式和饮食，以及所需的生物统计和定性研究方法方面拥有丰富的经验。该项目将在凯撒永久健康研究中心进行，这是一个设备齐全的研究中心，与俄勒冈健康科学大学合作，任务是在公共领域进行生物医学研究。

The annual cost of osteoporosis-related fractures in the US is $8 billion, most of which is borne by women in spite of an abundance of research on factors that might ameliorate the postmenopausal drop in bone mineral density (BMD). An important component of a lifelong prevention strategy would be to create methods for young women in the years 14-20 to maximize their bone mineral content and maintain it until menopause. This proposal will rigorously test two comprehensive lifestyle interventions, both oriented toward healthy diet and sustainable exercise, one based on individual counseling and the other on group intervention, against an attention control. The aim is to build bone and prevent bone loss among young women 14 to <16 years of age at recruitment. This trial draws upon our experience in 2 important studies of teens and nutrition--the Teen Lifestyle Project, DISC--and the ongoing fruit and vegetable study, DASH. The design is a parallel-group randomized clinical trial. with 300 participants equally divided among the groups, and measurements at baseline and three follow-ups to 27 months. This will provide power 0.90 to detect differences of l%-2% in TBBMD rates of change between groups. Secondary analysis will compare the achievement of the diet and exercise goals as compared to control, measured by objective markers (serum folate and carotenoids urinary sodium, lean body mass, accelerometer measure of physical activity) as well as by self-reports. The tertiary analysis will examine the same diet and exercise outcomes between the two intervention groups. and also in relation to process measures (adherence, evaluations, retention). The final analysis will explore potential causal pathways to bone mineral health involving a wider variety of factors, such as family history, biological and behavioral factors, hormonal influences and markers of bone metabolism. The investigators have a substantial amount of expertise in behavioral modification, research on teenage girls, nutrition and exercise interventions. They have substantial experience with assessment of bone mineral, body strength, exercise patterns, and diet, and with the biostatistical and qualitative research approaches required. The project will be carried out at the Kaiser Permanente Center for Health Research, a fully equipped research center with a mission of biomedical research in the public domain, in collaboration with the Oregon Health Sciences University.