PREDICTORS OF STRESS FRACTURE IN ACTIVE ADOLESCENT FEMALES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。自1972年《教育修正案》第九条（Title IX of the Educational Amendments Act）颁布以来，参加体育运动在青春期女性中变得越来越普遍。该法案要求女生参加的校际体育活动必须与她们在学生群体中的比例相称。这一趋势受到青少年卫生保健提供者的欢迎，因为积极的生活方式对健康有显著的好处。对年轻女性来说，一个特别的好处是有可能改善骨骼健康。青春期是年轻女性一生中骨量获取的关键时期，超过一半的成人骨钙是在青少年时期形成的，女性骨密度的峰值可能在10到30岁之间达到。负重运动是骨骼重塑的主要刺激，增加骨矿化，从而增加骨密度。通过在青春期参加体育运动来最大化骨密度（BMD）可能会导致这些年轻女性在以后的生活中预防骨质疏松症。骨质疏松症是目前超过2000万美国老年妇女发病和死亡的主要原因。对导致青春期女孩应力性骨折的因素知之甚少。我们假设许多风险因素与成年女性相同，并开发了一个发病模型来描述和解释它们之间的关系。我们假设只有低骨密度和运动直接影响应力性骨折的风险。我们进一步假设闭经通过对骨密度产生负面影响而增加应力性骨折的风险。作为青少年卫生保健提供者，我们为缺乏证据来回答“多少运动是安全的？”这个问题而烦恼。我们特别关注患有闭经的年轻女性参加运动的安全性。我们目前的护理标准要求用双能x线吸收仪（DXA）评估骨密度

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Athletic participation has become increasingly common among adolescent females since the enactment of Title IX of the Educational Amendments Act in 1972, which required women's intercollegiate athletic offerings to be proportional to their representationin the student body. This has been a welcome trend to adolescent health care providers, as there are notable health benefits derived from an active lifestyle. A particular benefit for young women is the potential for improved skeletal health. Adolescence is the critical period in a yound woman's life for bone mass acquisition, with over half of the adult bone calcium laid down during the teenage years and a woman's peak bone density likely reached between the ages of 10 and 30 years. Weight-bearing exercise is a major stimulus for skeletal remodeling, increased bone mineralization, and thereby, increased bone density. maximizing bone mineral density (BMD) by participation in athletics during adolescence could result in the prevention of osteoporosis later in these young women's lives. Osteoporosis is currently a mojor cause of morbidity and mortality for over 20 million American women in their later years. Less is known about factors that contribute to stress fractures in adolescent girls. We hpothesize that many of the risk factors are the same as in adult women and have developed a pathogenetic model to describe and explain the relationships among them. We hypothesize that only low BMD and exercise directly influence the risk of stress fracture. We further hypothesize that amenorrhea increases the risk of stress fracture by negaively impacting on BMD. As adolescent health care providers, we are vexed by the lack of evidence upon which to answer the question, "How much exercise is safe?" We are particularly concerned about the safety of athletic participation by young women with amenorrhea. Our current standard of care calls for assessment of bone density by dual energy x-ray absorptiometry (DXA) in