Effects of Hormone Therapy and Exercise on Bone Mineral Density in Healthy Women-A Systematic Review and Meta-analysis.

CONTEXT: There is some evidence that an adequate "anabolic hormonal milieu" is essential for the mechanosensitivity/transduction/response of bone tissue. OBJECTIVE: This work aimed to determine whether enhancing hormone therapy (HT) with exercise increases the isolated effect of HT on bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN). METHODS: A comprehensive search of 6 electronic databases according to the PRISMA statement up to April 28, 2021, included controlled trials longer than 6 months with 3 study arms: (a) HT, (b) exercise, and (c) HT plus exercise (HT + E). Apart from HT, no pharmaceutic therapy or diseases with relevant osteoanabolic or osteocatabolic effect on bone metabolism were included. The present analysis was conducted as a random-effects meta-analysis. Outcome measures were standardized mean differences (SMD) for BMD changes at the LS and FN. RESULTS: Our search identified 6 eligible studies (n = 585). Although the effect of HT + E was more pronounced in the LS (SMD: 0.19; 95% C,: -0.15 to 0.53) and FN-BMD (0.18; -0.09 to 0.44) compared to the HT group, we did not observe significant differences between the 2 groups. We observed a low (I2: 29%) or moderate (I2: 49%) level of heterogeneity between the trials for FN or LS. CONCLUSION: We do not observe a significant effect of HT + E vs HT alone. We largely attribute this result to varying HT supplementation and hormonal status. Bearing in mind that synergistic/additive effects between HT and mechanical stimulation can only be expected in situations of hormonal insufficiency, further clinical studies should consider baseline endogenous estrogen production but also HT dosing more carefully.