Effect of the metabolic syndrome on male reproductive function: a case-controlled pilot study

The metabolic syndrome (MetS) is a constellation of various risk factors. This study aimed to investigate the effect of MetS on testosterone and progesterone, and semen parameters, in a case-controlled pilot study. Male patients (n=54) had body mass index, waist-to-hip ratio (WHR) and blood pressure recorded. Blood was analysed for HDL cholesterol, triglycerides and glucose. Saliva was assayed for free testosterone and free progesterone. Ejaculates were analysed for volume, sperm concentration, total sperm count, motility, vitality, mitochondrial membrane potential (MMP), DNA fragmentation and leucocyte concentration. Participants were divided into the control group (n=28) and the MetS group (n=26). Differences were found between the groups for body mass index, WHR, blood pressure, high-density lipoprotein (HDL), triglycerides and glucose. The MetS group showed significant reductions in sperm concentration (P=0.0026), total sperm count (P=0.0034), total motility (P=0.0291), sperm vitality (P=0.002), MMP (P=0.0039), free testosterone (P=0.0093) and free progesterone (P=0.0130), while values for DNA fragmentation increased (P=0.0287). Results indicate that patients with MetS have compromised sperm parameters in the absence of leucocytospermia. A reduction in free progesterone suggests that steroidogenesis cascades may be compromised. It is hypothesised that a systemic pro-inflammatory state with oxidative stress associated with MetS may provide a novel explanation.