title: A randomized controlled trial of estrogen replacement therapy in long-term users of depot medroxyprogesterone acetate.
abstract: Long-term use of the injectable contraceptive depot medroxyprogesterone acetate (DMPA, Depo-Provera) is associated with a reduction in bone mineral density (BMD), particularly in the lumbar spine. The cause of DMPA-associated bone loss is not known, but the relative estrogen deficiency induced by DMPA use could be responsible. We have undertaken a randomized, double-blind controlled trial of oral estrogen replacement therapy in 38 premenopausal women (mean age 37) with a minimum 2 yr DMPA use who had a below average baseline lumbar spine BMD (T score < or = 0). Nineteen women were allocated to receive conjugated estrogens (0.625 mg/d orally) and 19 to receive a matching placebo. All continued with regular DMPA injections throughout the study. Areal bone density was measured by dual energy x-ray absorptiometry at the lumbar spine, femoral neck, and total body sites every 6 months for 2 yr; the main outcome measure being the change in areal BMD at the lumbar spine. At baseline, the two groups were well matched for demographic, anthropometric, and biochemical variables, and for BMD. Twenty-seven subjects completed at least 18 months in the study, and 26 the full 2 yr, with similar numbers dropping out from each group (mainly for personal reasons). In the estrogen-treated group, mean lumbar spine BMD increased 1%, whereas in the placebo group it fell 2.6%, over 2 yr. The between group differences were 2.0% at 12 months (P = 0.058), 3.2% at 18 months (P < 0.01), and 3.5% at 24 months (P < 0.002). Differences of lesser statistical magnitude were seen at the femoral neck (between group differences at 2 yr: 2.7%, P = 0.24), Ward's triangle (5.0%, P = 0.055), greater trochanter (3.6%, P = 0.056), total body (1.3%, P = 0.046), legs (1.3%, P = 0.065), and trunk (2.0%, P = 0.029). There were no major adverse events. These data support the view that the likely cause of DMPA-associated bone loss is estrogen deficiency and demonstrate that it can be arrested by estrogen replacement therapy.
authors.affiliation: Department of Medicine, Faculty of Medicine & Health Science, University of Auckland, 1001 Auckland, New Zealand. t.cundy@auckland.ac.nz
authors.forename: Tim
authors.initials: T
authors.lastname: Cundy
authors.forename: Ruth
authors.initials: R
authors.lastname: Ames
authors.forename: Anne
authors.initials: A
authors.lastname: Horne
authors.forename: Judy
authors.initials: J
authors.lastname: Clearwater
authors.forename: Helen
authors.initials: H
authors.lastname: Roberts
authors.forename: Greg
authors.initials: G
authors.lastname: Gamble
authors.forename: Ian R
authors.initials: IR
authors.lastname: Reid
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects; D003271:Contraceptive Agents, Female / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000378:metabolism; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D003271:Contraceptive Agents, Female; D003692:Delayed-Action Preparations; D017258:Medroxyprogesterone Acetate