DEPO PROVERA AND BONE MINERAL DENSITY IN ADOLESCENTS

描述：（改编自研究者摘要）美国有一个 是工业化国家中青少年怀孕率最高的国家之一。 一 其中一个主要因素是避孕措施不足。 一个非常 有效避孕方法是醋酸甲孕酮（DMPA） 在这个年龄段的人中越来越流行 最近的研究 成年人的研究表明DMPA对骨矿物质密度（BMD）有负面影响。 随着骨密度的降低，一个人以后患骨质疏松症的风险增加， 每年影响数百万绝经后妇女的公共卫生问题。 BMD受损似乎是青少年的一个特别问题， 在这一过程中，它们通常会积累高达40%的总骨矿物质含量， 期 在初步工作中，调查人员证明， 2年以上DMPA使用者的BMD增加了9.0%， 未处理的对照（p<0.0001）。 一项前瞻性队列研究， DMPA对青少年BMD的影响，还将包括一项双盲随机 预防措施，提出。 400例DMPA青少年骨密度测定 启动器将与其基线值和300的基线值进行比较， 120，口服避孕药和屏障避孕药启动者，分别，频率 年龄和种族都匹配 每六个月测量一次骨密度， 最多两年。 还将在以下时间测量骨密度： 停止避孕方法。 为了评估保护效果， 雌激素对骨密度的影响，DMPA治疗组的女性将 随机分配至含雌二醇的DMPA组（n=200）和不含雌二醇的DMPA组 （n=200）。 研究年龄是否影响DMPA的作用 在骨密度方面，研究人员将评估年龄-治疗的相互作用， DMPA使用与不同妇科年龄女性骨密度之间的关系。 最后，将比较性激素水平和钙代谢指标 以探讨其生物学机制 潜在的BMD变化。 统计分析将估计 DMPA对骨密度的影响 在整个研究期间停药。

DESCRIPTION: (Adapted from Investigator's Abstract) The United States has one of the highest adolescent pregnancy rates among industrialized nations. One of the major contributing factors is inadequate contraception. A very effective contraceptive method is depot-medroxyprogesterone acetate (DMPA) which has become increasingly popular in this age group. Recent research in adults has suggested a negative effect of DMPA on bone mineral density (BMD). With decreased BMD, one's risk increases later for osteoporosis, a major public health problem affecting millions of postmenopausal women every year. Compromised BMD would appear to be a particular concern in adolescents, as they normally accrue up to 40% of their total bone mineral content during this period. In preliminary work, the investigators demonstrated a 3.0% decrease in BMD in adolescent DMPA users over 2 years, compared with a 9.0% increase in untreated controls (p<0.0001). A prospective cohort study of the effects of DMPA on adolescent BMD, which will also include a double-blinded randomized prevention component, is proposed. Bone density in 400 adolescent DMPA initiators will be compared to their baseline values and to that of 300 and 120, oral and barrier contraceptive initiators, respectively, frequency matched on age and race. Bone density will be measured every six months for a maximum of two years. Bone density will also be measured at the time of discontinuation of contraceptive method. To evaluate the protective effects of estrogen on bone density, females in the DMPA treatment arm will be randomly assigned to DMPA with estradiol (n=200) and DMPA without estradiol (n=200). To examine the question of whether age modifies the effect of DMPA on bone density, the investigators will evaluate the age-treatment interaction between DMPA use and bone density among females of varying gynecologic ages. Finally, sex hormone levels and indices of calcium metabolism will be compared among the treatment groups in order to explore the biologic mechanisms underlying BMD changes. The statistical analysis will estimate the effect of DMPA on bone density while taking account of constant treatment discontinuation throughout the study period.