Serum osteocalcin and urinary crosslaps are suitable markers of bone turnover in response to short-term hormone replacement therapy

In this study we evaluated the effect of short-term hormone replacement the rapy (HRT) on bone formation (serum osteocalcin) and resorption markers (ur inary type I collagen peptides (crosslaps), urinary total free pyridinoline (TPYRI) and urinary free deoxypyridinoline (DPYRI)) as well as female sex hormones (serum estradiol, follicle stimulating hormone (FSH) and luteinizi ng hormone (LH) in a group of early postmenopausal women with severe estrog en deficiency. The 46 healthy postmenopausal women with serum estradiol lev els < 10 ng/l were subsequently divided into two groups, according to their compliance with HRT. In the group taking HRT significant changes from baseline values could be o bserved in estradiol, FSH, urinary crosslaps and serum osteocalcin levels a fter 6 months, whereas no changes could be observed in LH, TPYRI and DPYRI from baseline values. In the group which refused HRT all values were increa sed relative to baseline values, indicating increased bone turnover. Serum osteocalcin and urinary crosslaps were significantly decreased in wom en taking HRT in comparison to the group refusing HRT. After 6 months the t reated patients showed a decrease in urinary crosslaps of 42% (SD 12%) and in serum osteocalcin of 24% (SD 6%) in comparison with baseline values. In patients who refused HRT, urinary crosslaps were increased by 43% (SD 20%) and serum osteocalcin levels decreased by 2% (SD 9%) compared to baseline v alues. In postmenopausal women suffering from severe estrogen deficiency (estradio l < 10 ng/l) serum osteocalcin and urinary crosslaps are significantly incr eased, indicating a clear correlation between estrogen deficiency and an in crease in bone resorption as well as bone formation. The recommended HRT do se was sufficient to reduce the rate of bone turnover to premenopausal valu es. Serum osteocalcin and urinary crosslaps are suitable candidates not onl y for the assessment of a high postmenopausal bone turnover, but also for m onitoring the response to and for verifying the actual intake of HRT or oth er antiresorptive treatment.