Endocrine Abstracts

Purpose: To determine the effect of endogenous calciotropic and sex hormone concentration on bone parameters in postmenopausal women.

Methods: We analyzed baseline data of the Senior Fitness and Prevention Study (SEFIP), an 18-month randomized controlled exercise trail with 246 females, 65 years and older. Baseline assessments of Bone Mineral Density at the lumbar spine (LS) and proximal femur were performed using DXA technique. Blood samples were taken from each participant after an overnight fast between 0700 and 0900 h. Serum-estradiol, testosterone, SHBG, DHEA-S, vitamin-D (25OHD) and PTH (Roche Diagnostics, Mannheim, Germany) were determined. For each of these independent parameter our cohort was grouped into terziles with the same numbers of subjects according to the hormonal concentration. Here, we focus on the comparison of spinal and femoral BMD between the highest (1) vs the lowest terzile (3).

Results: Significant (P<0.01) between group-differences in respect to the BMD at LS and hip were observed for Estradiol (1>3), SHBG (1<3) and the Estradiol/SHBG fraction (1>3). Although there was a tendency for higher BMD-values in the highest terzile (1) significance could not be reached for Testosterone, DHEA-S and 25OHD. No difference at all was determined for PTH.

Conclusion: Estradiol, SHBG and ‘bioavailable’ Estradiol clearly predict BMD at the lumbar spine and femoral neck in postmenopausal females 65 years and older.