LIFESTYLE CHANGE TO INCREASE BONE DENSITY IN TEEN GIRLS

在美国，每年骨质疏松相关骨折的费用高达80亿美元，其中大部分由女性承担，尽管有大量关于可能改善绝经后骨密度下降的因素的研究。终身预防策略的一个重要组成部分是为14-20岁的年轻女性创造方法，使她们的骨矿物质含量最大化，并保持到更年期。该提案将严格测试两种全面的生活方式干预，都以健康饮食和可持续运动为导向，一种基于个人咨询，另一种基于群体干预，反对注意力控制。其目的是在招募时为14至16岁的年轻女性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）和正在进行的水果和蔬菜研究（DASH）。设计为平行组随机临床试验。300名参与者被平均分配到不同的组中，在基线和三个27个月的随访中进行测量。这将提供0.90的功率来检测组间TBBMD变化率的1% -2%的差异。二次分析将比较饮食和运动目标的实现情况，与对照组相比，通过客观指标（血清叶酸和类胡萝卜素尿钠，瘦体重，身体活动加速度计测量）以及自我报告来衡量。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。同时也涉及到过程度量（坚持，评估，保留）。最后的分析将探索骨矿物质健康的潜在因果途径，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志物。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学和定性研究方法方面有丰富的经验。该项目将在Kaiser Permanente健康研究中心进行，该中心是一个设备齐全的研究中心，与俄勒冈健康科学大学合作，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.