Osteoporosis International

, Volume 14, Issue 10, pp 814–822

Effects of raloxifene, hormone replacement therapy, and placebo on bone turnover in postmenopausal women

  • Robert S. Weinstein
  • A. Michael Parfitt
  • Robert Marcus
  • Maria Greenwald
  • Gerald Crans
  • Douglas B. Muchmore
Original Article

DOI: 10.1007/s00198-003-1434-z

Cite this article as:
Weinstein, R.S., Parfitt, A.M., Marcus, R. et al. Osteoporos Int (2003) 14: 814. doi:10.1007/s00198-003-1434-z

Abstract

Raloxifene, a nonsteroidal selective estrogen receptor modulator (SERM), increases bone mineral density (BMD), decreases biochemical markers of bone turnover, and prevents incident vertebral fractures in postmenopausal women, while sparing the breast and endometrium from the undesirable stimulation caused by estrogen. How the long-term beneficial effects of raloxifene on bone turnover, as assessed by bone histomorphometry, compare with hormone replacement therapy (HRT) and placebo are not known. We studied 66 healthy postmenopausal women (age 55 to 75 years, mean 63 years) who were randomized to either raloxifene 150 mg/day, HRT (Premarin 0.625 mg/day, and Provera 2.5 mg/day), or placebo for 1 year. All women received 1–1.5 g of calcium/day. Following double tetracycline labeling, transiliac bone biopsies were obtained at baseline and 1 year and analyzed for changes in histologic indexes of bone remodeling on the cancellous surface as well as at the endocortical subdivision of the endosteal envelope, the location of the greatest fraction of postmenopausal bone loss. BMD and biochemical markers of bone turnover were also determined at baseline and 1 year. Four paired biopsies were obtained in the HRT group, six in the raloxifene group, and five in the placebo group. The frequency of remodeling events on cancellous bone and rate of bone formation in both cancellous and endocortical bone increased in the placebo group, while these measurements decreased in both drug treatment groups. Using analysis of mean percentage changes, when compared with the placebo group, these changes were significantly different for both raloxifene and HRT treatment groups (p<0.02). In all subjects, the bone was lamellar with discrete tetracycline labels and there was no evidence of marrow fibrosis or abnormal bone cells. BMD increased from baseline at the lumbar spine (p<0.05 in the HRT group) and in the total body (p<0.05 for both raloxifene and HRT). Compared with that of the raloxifene group, the increase in BMD was greater in the HRT group at the lumbar spine but not in the total body. Serum bone alkaline phosphatase, serum osteocalcin, and urine C-terminal cross-linking telopeptide of type I collagen significantly decreased (p<0.05) in both active treatment groups, changes significantly different from those seen with placebo. Overall, these results support the hypothesis that raloxifene preserves bone mass by reducing the elevated bone turnover found in postmenopausal women receiving placebo, by mechanisms similar to those operative in postmenopausal women receiving HRT.

Keywords

Activation frequencyBone formationBone histomorphometryCancellous boneEndocortical boneSERM

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2003

Authors and Affiliations

  • Robert S. Weinstein
    • 1
  • A. Michael Parfitt
    • 1
  • Robert Marcus
    • 2
    • 5
  • Maria Greenwald
    • 3
  • Gerald Crans
    • 4
  • Douglas B. Muchmore
    • 4
  1. 1.Center for Osteoporosis and Metabolic Bone Diseases, Division of Endocrinology and Metabolism, Central Arkansas Veterans Healthcare SystemUniversity of Arkansas for Medical SciencesLittle RockUSA
  2. 2.VA Medical CenterPalo AltoUSA
  3. 3.Osteoporosis Medical CenterPalm DesertUSA
  4. 4.Eli Lilly and CompanyIndianapolisUSA
  5. 5.Eli Lilly and CompanyIndianapolisUSA