Endocrine Abstracts

Introduction: Hormonal replacement therapy (HRT) increases bone mineral density (BMD). Controversy exists regarding residual effect after withdrawal. We aimed to explore the effect of HRT and HRT withdrawal on: i) BMD and bone microarchitecture assessed by trabecular bone score (TBS); ii) fat (FMI), lean (LMI) and appendicular lean (ALMI) mass indexes.

Methods: The OsteoLaus Cohort assessed 1500 women (50–80 years) for BMD, TBS, total energy expenditure (TEE), alternative health eating index (AHEI) and depression prevalence. 1094 women had body composition analysis by dual X-ray absorptiometry. According to HRT status, women were classified as: Never (NU=504), Current (CU=205) and Past (PU=262) users.

Results: The three groups differed in age (67.4±6.8, 64.0±6.8, 62.1±8.0 for PU, CU and NU respectively, P<0.001), AHEI and TEE but not in BMI or depression prevalence. HRT users presented higher age- and BMI-adjusted TBS (CU and PU versus NU, P<0.001 and P=0.066 respectively) and BMD at lumbar spine (LS) and total hip (TH) (CU and PU versus NU, P<0.05). TBS was negatively associated with age and BMI-adjusted slopes for 10-year increment were −0.051 (−0.060; −0.041), −0.032 (−0.048; −0.017) and −0.022 (−0.038; −0.005) (NU, PU and CU respectively, P<0.05). Slopes of LS and TH BMD showed similar pattern (NU<PU<CU, P<0.015). After multiple adjustments, no difference existed between the 3 groups for LMI and ALMI. Slopes for 10-year increment of FMI were 0.887 (0.566; 1.208), 0.084 (−0.463; 0.631) and 0.225 (−0.350; 0.800) for NU, PU and CU respectively (CU or PU versus NU, P<0.05).

Conclusion: Current HRT use is associated with higher BMD values and better preservation of TBS. The benefits of HRT seem to persist in PU. HRT has no effect on lean mass. However, the age-associated gain of FMI is reduced in HRT users. Further analysis is ongoing to assess whether it concerns subcutaneous or visceral fat.