Bone mineral density and biochemical markers of bone turnover in peri- and postmenopausal women

Bone mineral density (BMD) measured by densitometry is the elective parameter for the diagnosis of osteopenia and osteoporosis. Biochemical markers have been proposed as sensitive indicators of high bone turnover and for monitoring response to antiresorptive treatment. We conducted a retrospective study to investigate the values of biochemical markers of bone metabolism with a view to early diagnosis of osteoporosis and monitoring of hormone replacement and calcitonin therapy. The subjects were 415 women, mean age 51 ± 8 years (43-62 years) in peri- and postmenopause, recruited at the Menopause Center of Obstetrics and Gynecology Department of Siena University and divided in five groups. Bone densitometry was performed in all subjects and blood samples were taken for assayed biochemical markers, that is, [osteocalcin (OC), parathyroid hormone (PTH), type 1 procollagen (PICP), and calcitonin (CT)]. Three groups of women were divided into two subgroups: those with normal and those with low BMD (<1 SD). Basal concentrations of PCP1, OC, PTH, and CT were compared in the various groups. Two groups of postmenopausal women with BMD below the normal were treated with estrogen replacement therapy and unmodified eel calcitonin. We evaluated whether some of these biochemical markers of bone turnover could help identify women with low BMD and whether they could be useful for monitoring the results of antiresorptive therapies. Markers of bone formation (PICP and OC) make it possible to distinguish women with high turnover who are at risk for osteoporosis from women with low turnover in menopause. A good correlation was also found between changes in levels of these markers and changes in BMD during treatments, which suggests that the PICP and OC would be useful for monitoring response to antiresorptive therapy.