Is there any effect of insulin resistance on male reproductive system?

To investigate the possible effect of insulin resistance (IR) on male reproductive system via evaluation of semen analysis, male sex hormones and serum lipid profiles, and testicular volumes.

After the exclusions, a total of 80 male patients were enrolled in this prospective study. Body Mass Index (BMI), Testicular volume, semen samples, serum hormone/lipid profiles, high sensitive C-Reactive Protein (hsCRP) were obtained from all the subjects.

The patients were divided into two groups as study and control according to the presence of IR. There were no statistical differences in terms of age, marriage period, testicular volume, serum levels of hormone and lipid profiles and BMI between the groups. There were no relationship between homeostasis model assessment of insulin resistance (HOMA-IR) and semen volume (r = -0.10, p = 0.37), total sperm count (r = -0.09, p = 0.39), motility (r = -0.15, p = 0.16) and morphology (r = -0.14, p = 0.19). However, HOMA-IR was closely associated with hsCRP levels (r = 0.94, p < 0.0001).

Despite of the documented strong inverse relationships between Diabetes Mellitus (DM) and male/female fertility, and also between IR and female infertility via ovarian functions as in polycystic ovary syndrome, to our knowledge, there is no report about any influence of IR on male fertility. DM and metabolic syndrome (MetS) have negative influence on fertility. Thus, IR may be accused of causing detrimental effect on male infertility due to hyperinsulinemic state and being one of the components for MetS. Interestingly, due to our preliminary results, we do not found any inverse correlation between IR and male reproductive functions.