title: Changes in bone density and turnover after alendronate or estrogen withdrawal.
abstract: OBJECTIVE
  To compare bone mineral density (BMD) and bone turnover changes after therapy withdrawal in postmenopausal women treated with alendronate or estrogen-progestin.
  
  
  METHODS
  In this randomized, blinded, multinational, placebo-controlled trial, 1,609 healthy postmenopausal women ages 45 to 59 years were assigned to receive alendronate, placebo, or open-label estrogen-progestin (conjugated equine estrogens plus medroxyprogesterone acetate or a cyclic regimen of 17 beta-estradiol, norethisterone acetate and estradiol). Of the original women, one third after year 2 and one third after year 4 were switched from alendronate to placebo, while remaining blinded to treatment assignment. The women taking estrogen-progestin in years 1 to 4 were followed off therapy in years 5 and 6. BMD at the lumbar spine and hip and biochemical markers of bone turnover were measured.
  
  
  RESULTS
  The treatment groups described in the current report represent 860 women at baseline; 481 women entered year 5, and 430 completed 6 years. BMD steadily decreased in the placebo group during all 6 years. In contrast, spine and hip BMD increased during the first 4 years in the groups receiving daily continuous alendronate 5 mg and estrogen-progestin. During years 5 and 6, BMD decreased at the lumbar spine -2.42% (95% CI = -4.10, -0.74) and total hip -1.09% (-2.60, 0.41) in the group previously treated with alendronate 5 mg for 4 years. In comparison, large BMD decreases were observed at the spine [-7.69% (-8.96, -6.41)] and total hip [-5.16% (-6.30, -4.01)] among women who had received estrogen-progestin for 4 years.
  
  
  CONCLUSIONS
  Alendronate produces greater residual skeletal effects than estrogen-progestin after therapy discontinuation.
authors.affiliation: Radiant Research-Honolulu, Honolulu, HI 96814, USA. richardwasnich@radiantresearch.com
authors.forename: Richard D
authors.initials: RD
authors.lastname: Wasnich
authors.forename: Yu Z
authors.initials: YZ
authors.lastname: Bagger
authors.forename: David J
authors.initials: DJ
authors.lastname: Hosking
authors.forename: Michael R
authors.initials: MR
authors.lastname: McClung
authors.forename: Mei
authors.initials: M
authors.lastname: Wu
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Mantz
authors.forename: John J
authors.initials: JJ
authors.lastname: Yates
authors.forename: Philip D
authors.initials: PD
authors.lastname: Ross
authors.forename: Peter
authors.initials: P
authors.lastname: Alexandersen
authors.forename: Pernille
authors.initials: P
authors.lastname: Ravn
authors.forename: Claus
authors.initials: C
authors.lastname: Christiansen
authors.forename: Arthur C
authors.initials: AC
authors.lastname: Santora
mesh_terms: D000368:Aged; D019386:Alendronate / Q000008:administration & dosage*; D015519:Bone Density; D016723:Bone Remodeling; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004958:Estradiol / Q000008:administration & dosage; D015914:Estrogen Replacement Therapy; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage; D005260:Female; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage; D008875:Middle Aged; D009640:Norethindrone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000077563:Norethindrone Acetate; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D004966:Estrogens, Conjugated (USP); D004958:Estradiol; D000077563:Norethindrone Acetate; D017258:Medroxyprogesterone Acetate; D009640:Norethindrone; D019386:Alendronate