The effects of testosterone on bone health in males with testosterone deficiency: a systematic review and meta-analysis

Background Testosterone deficiency (TD) may induce a series of clinical symptoms. Studies have shown that testosterone supplementation may prevent these unfavourable symptoms and improve patients' quality of life. Given the conflicting findings across studies, this systematic review aims to evaluate the effects and risks associated with testosterone supplementation in middle-aged or aging males with TD. Methods Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane. Library were searched to December 2019. The risk of bias of individual included studies and the quality of the aggregate evidence were assessed using the GRADE approach. Our primary outcome was bone mineral density (BMD). Meta-analyses were performed. This systematic review was reported according to the PRISMA statement. Results A total of 52 randomized controlled trials (RCTs) were included. When compared with placebo, testosterone supplementation did not increase total BMD (short-term: 1081 participants, MD - 0.01 g/cm(2), 95% CI - 0.02 g/cm(2) to 0.01 g/cm(2); long-term: 156 participants, MD 0.04 g/cm(2), 95% CI - 0.07 g/cm(2) to 0.14 g/cm(2)), lumbar spine, hip, or femur neck BMD. Furthermore, testosterone supplementation did not decrease the risk of falling or fracture. Lastly, it was found that testosterone supplementation did not increase the risk of cardiovascular events (1374 participants, RR 1.28, 95% CI 0.62 to 2.64), all-cause mortality (729 participants, RR 0.55, 95% CI 0.29 to 1.04), or prostatic events. However, testosterone supplementation may improve sexual function and quality of life (1328 participants, MD -1.32, 95% CI - 2.11 to - 0.52). Conclusions The effect of testosterone supplementation on BMD and the risk of falls or fracture remains inconclusive. However, supplementation may benefit patients in the areas of sexual function and quality of life without increasing the risk of cardiovascular events, all-cause mortality, or prostatic events. RCTs with a longer follow-up period are still required.