RF06 | PSAT152 Associations between Bone Mass, Hormone Levels and Body Composition in Postmenopausal Women

Emerging evidence suggests an association between FSH and bone mass in peri- and postmenopausal women. The aim of the present study was to assess body composition parameters and hormone levels as risk factors for low bone mass in women with recent menopause. In this cross-sectional study, we analyzed biorepository samples from 139 postmenopausal women aged 42 to 68 years with no evidence of clinical CVD. Inclusion criteria were as follows: menopause, defined as last menstrual period at least 12 months of amenorrhea and/or 6 months or more of amenorrhea plus FSH levels ≥35 mIU/mL occurring after 40 years of age, and no use of hormone therapy (HT) in the past 3 month. BMD and body composition were assessed by dual-energy X-ray absorptiometry (DXA), SHBG and FSH levels were measured in all patients. Serum estradiol levels were measured by gas chromatography/tandem mass spectrometry assay (GC/MS/MS) in a subset of 57 participants and free estrogen index (FEI) was estimated by dividing estradiol by SHBG × 100. Low bone mass was considered osteoporosis and osteopenia. The mean age was 54.33±5.30 years and median time since menopause was 4 (2 - 9) years. The mean BMI was 26.73±4.38 kg/m(2) and 66% of participants were classified as overweight or obese. BMI, BMD and T-sc, lean mass index (LMI) and fat mass index (FMI) were lower, and SHBG was higher in women with FSH levels above the median values (83.6mUI/mL). FSH was inversely correlated with FEI (rho=-0.283, p=0.033) as well as with FMI (rho=-0.288, p=0.001) and LMI (rho=-0.186, p=0.029), but significance was lost after adjustment for estradiol levels (p=0.651). In the univariate linear regression analysis, FSH, FEI, time since menopause, SHBG, FMI and LMI were significant predictors to total femur bone mass, explaining 3.8%, 11.9%, 7.4%, 14.7%, 19.7% and 8.4% of variance in BMD at this site, respectively. In the multivariate model, the association of FSH, time since menopause and FMI with hip bone mass was no longer significant after inclusion of FEI in the respective model. The present results indicate that the negative association between FSH levels and femoral BMD in postmenopausal women are influenced by endogenous estradiol levels, time since menopause and fat mass. Additional studies are needed in order to further analyze whether some direct effect of FSH on bone mass may be additive to the presence of low bone mass in this population. Presentation: Saturday, June 11, 2022 1:00 p.m. - 1:05 p.m., Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.