Oral Contraceptive Use and Bone Density in Young Women

描述（由申请人提供）：对于超过1000万使用口服避孕药（OC）的美国妇女，关于OC对健康影响的明确证据是一个主要的公共卫生问题。最近的几项研究表明，目前的OC制剂可能会抑制年轻女性的峰值骨量增加。然而，这种可能性尚未得到充分评估，特别是在青少年中使用OC方面，这是最积极获得骨骼的群体。本申请的重点是全面评估OC使用对年轻女性骨骼的影响。我们包括考虑不同的骨骼部位，不同的使用时间，和不同的OC雌激素含量。重要的是，据我们所知，这将是第一个记录OC停药后骨密度（BMD）变化的前瞻性研究。 我们提出了一个前瞻性的流行病学研究对骨的影响，新的和正在进行的OC使用和OC停止在一个队列的青少年和年轻的成年女性。该队列（n=600）将从14 - 30岁的HMO入组者中招募，其中300名参与者年龄为14-18岁，300名参与者年龄为19-30岁。每个年龄组将包括200名OC用户和100名比较女性。我们将评估低剂量（20 mcg EE）和高剂量（35 mcg EE）制剂可能产生的不同效应。HMO的自动药房和会员档案将用于选择新的和正在使用OC的妇女，并随机选择不使用激素避孕的妇女进行比较，年龄和诊所的频率匹配。参与者将接受24-36个月的纵向随访。将使用双能X线吸收测定法每6个月在选定的解剖部位（髋关节、脊柱、全身）测量一次主要结局（骨矿物质密度）。在我们迄今为止调查注射避孕药与青少年和年轻成年女性BMD之间关系的工作中，我们用类似的方法招募和保留了优秀的参与者，并制定了相关的测量和分析策略。 OC使用率在性活跃的青少年和20多岁的女性中最高。这些也是积极获得骨骼的女性。鉴于骨质疏松症对公共卫生的重要性日益增加，以及在生长的关键阶段暴露于OC的患病率，有针对性地评估OC使用对这些年轻女性骨骼健康的潜在不良影响-以及停止这种暴露后可能的改善-是至关重要的。

DESCRIPTION (provided by applicant): For the more than 10 million US women using oral contraceptives (OCs), clear evidence regarding the health effects of OCs is a major public health concern. Several recent studies suggest that current OC formulations may act to suppress peak bone mass accrual in young women. However, this possibility has not been fully evaluated, particularly with regard to OC use among adolescents, the group most actively gaining bone. This application is focused on a thorough evaluation of the impacts of OC use on bone in young women. We include consideration of different skeletal sites, varying durations of use, and differing OC estrogen content. Importantly, this would be the first prospective study to our knowledge to document changes in bone mineral density (BMD) after OC discontinuation. We propose a prospective epidemiologic study of the effects on bone of new and ongoing OC use and of OC discontinuation in a cohort of adolescent and young adult women. The cohort (n=600) will be recruited from a defined population of HMO enrollees between the ages of 14 and 30, with 300 participants aged 14-18 years and 300 aged 19-30. Each age group will include 200 OC users and 100 comparison women. We will evaluate possibly different effects from a low-dose (20 mcg EE) and a higher-dose (35 mcg EE) formulation. The HMO's automated pharmacy and membership files will be used to select women who are new and ongoing users of OCs and to randomly select comparison women who are not using hormonal contraception, frequency matching on age and clinic. Participants will be followed longitudinally for 24-36 months. The primary outcome, bone mineral density, will be measured every 6 months at selected anatomic sites (hip, spine, whole body) using dual-energy x-ray absorptiometry. In our work to date investigating the association between injectable contraception and BMD in adolescents and young adult women, we have achieved excellent participant recruitment and retention with similar methods and have developed relevant measurement and analytic strategies. OC use is highest among sexually active adolescents and women in their 20s. These are also women who are actively gaining bone. Given the increasing public health importance of osteoporosis and the prevalence of OC exposure at a crucial stage of growth, focused evaluation of the potentially adverse effects of OC use on the skeletal health of these young women--and their possible amelioration upon cessation of this exposure--is essential.