Cann C E
Department of Radiology, University of California, San Francisco, USA.
J Reprod Med. 1998 Mar;43(3 Suppl):321-30.
To outline the optimal use of bone densitometry in women receiving gonadotropin releasing hormone (GnRH) agonist therapy.
The use of bone densitometry during clinical trials of the use of GnRH agonists in endometriosis has resulted in a number of publications with varying conclusions about the effects of these agents on the skeleton. A review of this literature, taking into account known concepts of bone physiology and the varying quantities measured by different bone densitometry devices, was done to place these results into a common framework. Within this context, a proposal is made for when and how to use various bone densitometry methods in individual patients and how to interpret the results properly.
Bone density in young women being treated for endometriosis is usually within the normal range, with even those 2 SD below normal not at significant risk of osteoporotic fracture. However, the clinical results show that most, if not all, women treated with GnRH agonists experience an increase in bone turnover due to estrogen deficiency during treatment, and this can result in a transient decrease in bone density. Even though the bone is regained after treatment is stopped, it may take years to recover fully. For those women who had low bone density to start, they may lose sufficient bone to increase their risk of osteoporotic fracture, and it is important to identify those individuals before treatment and to monitor them carefully. If the result of a peripheral bone density measurement (hand, forearm, heel) or central measurement (spine or hip) before treatment is higher than about 1 SD below a young normal mean, then even if a woman loses some bone, she will not have a significant increase in the risk of fracture. However, if a measurement is low (> 1 SD below the mean, putting her in the lower 15%), then it is advisable to have a spinal measurement by quantitative computed tomography or dual energy x-ray absorptiometry before and after therapy to determine what the bone changes are and to follow-up after the end of treatment. This is especially true if she decides to become pregnant, needs retreatment with a GnRH agonist or will be going through natural menopause in the near future; all can cause further bone loss.
Different bone density methods give different information and must be interpreted properly when used in evaluating patients on GnRH agonist therapy. Any bone measurement may be used to assess skeletal status before treatment, but if a peripheral bone measurement is low, it should be followed with a spinal measurement by quantitative computed tomography or dual energy x-ray absorptiometry so that the effect of the treatment can be monitored. Bone loss is transient with GnRH treatment, but only spinal measurements have sufficient sensitivity to follow patients and evaluate the skeletal changes in a meaningful way.
概述骨密度测定法在接受促性腺激素释放激素（GnRH）激动剂治疗的女性中的最佳应用。
在子宫内膜异位症患者使用GnRH激动剂的临床试验中应用骨密度测定法，已产生了大量关于这些药物对骨骼影响的结论各异的出版物。考虑到已知的骨生理学概念以及不同骨密度测定设备所测量的不同量值，对该文献进行了综述，以便将这些结果置于一个通用框架内。在此背景下，针对何时以及如何在个体患者中使用各种骨密度测定方法以及如何正确解读结果提出了建议。
接受子宫内膜异位症治疗的年轻女性的骨密度通常在正常范围内，即使那些低于正常水平2个标准差的女性发生骨质疏松性骨折的风险也不高。然而，临床结果表明，大多数（如果不是全部）接受GnRH激动剂治疗的女性在治疗期间由于雌激素缺乏会出现骨转换增加，这可能导致骨密度短暂下降。尽管在停止治疗后骨密度会恢复，但可能需要数年才能完全恢复。对于那些开始时骨密度较低的女性，她们可能会流失足够的骨量，从而增加骨质疏松性骨折的风险，在治疗前识别出这些个体并对其进行仔细监测很重要。如果治疗前外周骨密度测量（手部、前臂、足跟）或中心测量（脊柱或髋部）的结果高于年轻正常均值以下约1个标准差，那么即使女性流失了一些骨量，其骨折风险也不会显著增加。然而，如果测量值较低（低于均值1个标准差以上，使其处于较低的15%范围内），则建议在治疗前后通过定量计算机断层扫描或双能X线吸收测定法进行脊柱测量，以确定骨变化情况，并在治疗结束后进行随访。如果她决定怀孕、需要再次使用GnRH激动剂治疗或在不久的将来即将经历自然绝经，情况尤其如此；所有这些情况都可能导致进一步的骨丢失。
不同的骨密度方法提供不同的信息，在用于评估接受GnRH激动剂治疗的患者时必须正确解读。任何骨测量都可用于评估治疗前的骨骼状态，但如果外周骨测量值较低，则应接着通过定量计算机断层扫描或双能X线吸收测定法进行脊柱测量，以便监测治疗效果。GnRH治疗导致的骨丢失是短暂的，但只有脊柱测量具有足够的敏感性来跟踪患者并以有意义的方式评估骨骼变化。
