Effects of Metabolic Syndrome on Semen Quality and Circulating Sex Hormones: A Systematic Review and Meta-Analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 32849258 · doi:10.3389/fendo.2020.00428
What was done
The authors conducted a systematic review and meta-analysis of public databases to evaluate the association between metabolic syndrome and semen quality and circulating sex hormones. Standardized mean differences and 95% confidence intervals were pooled using a random-effects model across 11 studies comprising 1,731 cases with metabolic syndrome and 11,740 controls.
What was found
Compared with controls, metabolic syndrome cases had statistically significant reductions in sperm total count (SMD: -0.96, 95% CI: -1.58 to -0.31), sperm concentration (SMD: -1.13, 95% CI: -1.85 to -0.41), sperm normal morphology (SMD: -0.61, 95% CI: -1.01 to -0.21), sperm progressive motility (SMD: -0.58, 95% CI: -1.00 to -0.17), sperm vitality (SMD: -0.83, 95% CI: -1.11 to -0.54), follicle-stimulating hormone (SMD: -0.87, 95% CI: -1.53 to -0.21), testosterone (SMD: -5.61, 95% CI: -10.90 to -0.31), and inhibin B (SMD: -2.42, 95% CI: -4.52 to -0.32). Metabolic syndrome was also associated with significant increases in sperm DNA fragmentation (SMD: 0.76, 95% CI: 0.45 to 1.06) and mitochondrial membrane potential (SMD: 0.89, 95% CI: 0.49 to 1.28). No significant differences were observed for semen volume, sperm total motility, luteinizing hormone, estradiol, prolactin, or anti-Müllerian hormone (P > 0.05).
Why it matters
This meta-analysis provides pooled quantitative evidence linking metabolic syndrome to impairment across multiple semen parameters and altered sex hormones, highlighting metabolic health as a potential risk factor in male infertility.
Limits
The findings rely on observational studies that cannot establish causality. The abstract does not report study-specific designs, diagnostic criteria for metabolic syndrome, statistical heterogeneity, or control for potential confounders such as age, smoking, and body mass index.
Cited by
- supports Insulin resistance, metabolic disease, and obesity are the primary modifiable risk factors driving the decline in male fertility and sperm parameters.