Effects of Anabolic Androgenic Steroids on the Reproductive System of Athletes and Recreational Users: A Systematic Review and Meta-Analysis.

BACKGROUND Anabolic androgenic steroids (AAS) are testosterone derivatives used by athletes and recreational users to improve athletic performance and/or enhance appearance. Anabolic androgenic steroids use may have serious and potentially irreversible adverse effects on different organs and systems, including the reproductive system. OBJECTIVE This systematic review and meta-analysis aimed to critically assess the impact of AAS use on the reproductive system of athletes and recreational users. METHODS An electronic literature search was conducted using the databases MEDLINE, CENTRAL, and Google Scholar. Studies were included when the following criteria were fulfilled: participants were athletes or recreational users of any age, sex, level or type of sport; AAS use of any type, dose, form or duration; AAS effects on the reproductive system were assessed as stated by medical history, clinical examination, hormone and/or semen analysis. Random-effects meta-analysis was performed to assess the weighted mean difference (WMD) of serum gonadotropin (luteinizing hormone, follicle-stimulating hormone) and testosterone levels compared with baseline, during the period of AAS use, as well as following AAS discontinuation. RESULTS Thirty-three studies (three randomized clinical trials, 11 cohort, 18 cross-sectional, and one non-randomized parallel clinical trial) were included in the systematic review (3879 participants; 1766 AAS users and 2113 non-AAS users). The majority of the participants were men; only six studies provided data for female athletes. A meta-analysis (11 studies) was conducted of studies evaluating serum gonadotropin and testosterone levels in male subjects: (1) prior to, and during AAS use (six studies, n = 65 AAS users; seven studies, n = 59, evaluating gonadotropin and testosterone levels respectively); (2) during AAS use and following AAS discontinuation (four studies, n = 35; six studies, n = 39, respectively); as well as (3) prior to AAS use and following AAS discontinuation (three studies, n = 17; five studies, n = 27, respectively). During AAS intake, significant reductions in luteinizing hormone [weighted mean difference (WMD) -3.37 IU/L, 95% confidence interval (CI) -5.05 to -1.70, p < 0.001], follicle-stimulating hormone (WMD -1.73 IU/L, 95% CI -2.67 to -0.79, p < 0.001), and endogenous testosterone levels (WMD -10.75 nmol/L, 95% CI -15.01 to -6.49, p < 0.001) were reported. Following AAS discontinuation, serum gonadotropin levels gradually returned to baseline values within 13-24 weeks, whereas serum testosterone levels remained lower as compared with baseline (WMD -9.40 nmol/L, 95% CI -14.38 to -4.42, p < 0.001). Serum testosterone levels remained reduced at 16 weeks following discontinuation of AAS. In addition, AAS abuse resulted in structural and functional sperm changes, a reduction in testicular volume, gynecomastia, as well as clitoromegaly, menstrual irregularities, and subfertility. CONCLUSION The majority of AAS users demonstrated hypogonadism with persistently low gonadotropin and testosterone levels, lasting for several weeks to months after AAS withdrawal. Anabolic androgenic steroid use results in profound and prolonged effects on the reproductive system of athletes and recreational users and potentially on fertility.