Gonadotropin-releasing hormone agonists and the skeleton.

OBJECTIVE: To review and evaluate published studies that have assessed the effect on the skeleton of treatment with gonadotropin-releasing hormone agonists (GnRH-a). The effects on bone biochemistry and bone density are presented. DATA IDENTIFICATION: Major studies reporting on bone and GnRH-a use were identified through Excerpta Medica and Medline searches. STUDY SELECTION: Those that have reported on GnRH-a treatment in patients where data relating to skeletal metabolism or bone density were obtained.
RESULTS: Changes in bone biochemistry during GnRH-a therapy indicate that there is altered skeletal metabolism associated with GnRH-a use. The data on changes in bone density after a 6-month course of GnRH-a therapy generally indicate some bone loss. The magnitude of any detected change in bone density depends on the skeletal site assessed and the method of assessment. No significant bone loss has been documented in cortical bone; any bone loss occurring is usually associated with trabecular bone and is partially or completely reversible on withdrawal of GnRH-a treatment.
CONCLUSIONS: A 6-month course of GnRH-a therapy may result in a small reduction in trabecular bone density that is partially or completely reversible on withdrawal of treatment. The magnitude of any persistent residual bone loss is unlikely to be of clinical relevance and the benefits of a single 6-month course of GnRH-a therapy should not be withheld on the basis of a possible effect on bone.