Estrogen Replacement and Alternatives for the Prevention and Treatment of Osteoporosis

V. L. Baker, U. Ulrich, R. N. Taylor

Research output: Contribution to journalReview article

Abstract

The adult human skeleton is subject to constant breakdown and synthesis, a phenomenon referred to as bone remodeling. After menopause, bone resorption may exceed bone formation. As a result, osteoporosis may develop - a disease that is characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and susceptibility to fracture. Bone densitometry is often used as a noninvasive means of diagnosing osteoporosis before fracture. The definition of osteoporosis, published in 1994 by the World Health Organization Osteoporosis Study Group, states that osteoporosis is present when the bone mineral density (BMD) is more than 2.5 SDs below the young adult mean. An assessment of BMD may often help the clinician and a woman decide whether to initiate therapy for osteoporosis prevention or to begin treatment. The National Osteoporosis Foundation currently recommends measuring BMD in any woman aged 65 years or over who is not already on treatment. Bone markers may have a role in the management of women with osteopenia or osteoporosis, but the high variability in the results from bone marker testing limits their value and must be considered when interpreting the results. The most widely used options for the treatment and prevention of osteoporosis, including estrogen, calcium, calcitonin, the bisphosphonates, and the selective estrogen receptor modulators, act primarily by inhibiting bone resorption. In this way, BMD may be increased by any of these therapies. An interesting finding from studies of hormone replacement, alendronate, tamoxifen, and raloxifene is that the magnitude of fracture prevention is greater than would be predicted from the changes in BMD. It is possible that bone quality may also be influenced by some of these therapies. There is controversy regarding the appropriate time to initiate therapy; some argue for initiation of therapy early for prevention of osteopenia, whereas others argue that the most important time to initiate therapy is later (after the diagnosis of osteopenia or osteoporosis). If all women, including women with normal BMD, are treated to prevent osteopenia, then many women will need to be treated to prevent a fracture. If therapy is not initiated until a fracture occurs, subsequent fracture risk will be reduced, compared with the risk present if no therapy is given. However, the risk of fracture may still be high, even with treatment, because of marked deterioration of bone architecture in women with fractures that may not be correctable with treatment at the advanced stage of disease. Thus, a reasonable strategy may be to treat women who have osteopenia or osteoporosis and to provide calcium supplementation and to follow up women with normal BMD. However, for therapies such as estrogen replacement, which affects tissues other than the bone, it may be desirable to initiate therapy in women with normal BMD to achieve benefits for other organ systems. Decisions regarding which therapy is most appropriate for an individual woman must take into account the impact of each therapeutic agent on a woman's total health. For example, a woman with osteoporosis and at high risk of breast cancer may prefer to take alendronate rather than hormone replacement. If long-term prevention of breast cancer is confirmed with selective estrogen receptor modulators such as raloxifene, this medication may prove to be the therapy of choice for such a patient. Hormone replacement would be preferable to other treatments for a woman with osteoporosis and symptomatic genital atrophy. Adequate calcium intake and exercise are important for all women. The total risk-benefit profile for each medication should be considered, as discussed throughout this monograph.

Original languageEnglish (US)
Pages (from-to)77-119
Number of pages43
JournalCurrent Problems in Obstetrics, Gynecology and Fertility
Volume22
Issue number3
StatePublished - Dec 1 1999
Externally publishedYes

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ASJC Scopus subject areas

  • Obstetrics and Gynecology

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