Comparison of the effects of two different types of calcium supplementation on markers of bone metabolism in a postmenopausal osteopenic population with low calcium intake: a double-blind placebo-controlled trial

Climacteric. 2004 Mar;7(1):33-40. doi: 10.1080/13697130310001651454.


Objective: To investigate calcium supplements in postmenopausal women. Calcium supplements in postmenopausal women with a low calcium intake have been shown to prevent osteoporotic vertebral fracture, but calcium is variably absorbed and often poorly tolerated, which may limit effectiveness.

Methods: The study compared the efficacy and tolerability of 500 mg/day of calcium in the form of ossein-hydroxyapatite (OHC) versus 500 mg/day of tricalcium phosphate (TCP) and placebo in the prevention of postmenopausal bone loss. This was a prospective randomized study enrolling 153 postmenopausal osteopenic women. Serum and urine markers of bone turnover were collected at 3 and 6 months. Bone density measurement was performed at baseline and 6 months in all participants, and at 12 months in women taking OHC.

Results: At 3 and 6 months, both TCP and OHC decreased serum markers of bone formation significantly, compared with placebo. At 6 months, TCP and OHC decreased osteocalcin by 9.9% and 12.3%, respectively; the aminoterminal propeptide of type I procollagen (PINP) was decreased by 5.3% and 6.3%, respectively; bone-specific alkaline phosphatase was decreased by 4.3% and 6.7%, respectively, compared with baseline. The effects on bone resorption markers or on bone mineral density did not reach statistical significance, although OHC increased bone density by 0.8% at the spine at 12 months. Both forms of calcium were well tolerated and did not differ from placebo in terms of side-effects.

Conclusions: While both OHC and TCP were well tolerated and significantly reduced bone turnover markers, the effect of ossein-hydroxyapatite seems slightly superior to that of tricalcium phosphate.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alkaline Phosphatase / analysis
  • Biomarkers / analysis
  • Bone Density / physiology
  • Bone Remodeling / drug effects*
  • Bone Remodeling / physiology
  • Calcium Phosphates / therapeutic use*
  • Collagen Type I / analysis
  • Double-Blind Method
  • Durapatite / therapeutic use*
  • Female
  • Humans
  • Osteocalcin / analysis
  • Osteoporosis, Postmenopausal / prevention & control*
  • Peptide Fragments / analysis
  • Prospective Studies
  • Reference Values


  • Biomarkers
  • Calcium Phosphates
  • Collagen Type I
  • Peptide Fragments
  • Osteocalcin
  • Durapatite
  • Alkaline Phosphatase
  • tricalcium phosphate