Biochemical bone markers and bone mineral density during postmenopausal hormone replacement therapy with and without vitamin D3: a prospective, controlled, randomized study.
The effects of postmenopausal hormone replacement therapy (HRT) and vitamin D on the serum concentrations of three bone biochemical markers and their associations with bone mineral density (BMD) were studied in a population-based 1-yr follow-up study. A total of 72 healthy postmenopausal women were randomized into 4 treatment groups: HRT group (sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate), D group (vitamin D3, 300 IU/day), HRT+D group (both of the above), and placebo group (calcium lactate, 500 mg/day). Serum concentrations of osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) were measured as biochemical markers of bone formation, and serum type I collagen carboxy-terminal telopeptide was measured as a marker of bone resorption at baseline and after 6 and 12 months of treatment. To investigate the associations of these markers with BMD, lumbar (L2-L4) and femoral neck BMDs were determined by dual x-ray absorptiometry at baseline and after 2.5 yr of treatment. In both hormone groups, the serum concentrations of the three bone metabolic markers had decreased after 12 months. Those of OC decreased by 29.2% (P = 0.017) in the HRT group and by 37.3% (P = 0.004) in the HRT+D group, and BAP concentrations decreased by 34.4% (P