Body Mass Index and Sperm Quality: Is there a Relationship?

Context: Obesity and infertility are the major global public health problems. The evidences of adverse impact of adiposity on male fertility are contradictory.

Aim: The objective of the study was to determine the effect of overweight and obesity on ejaculate quality, in particular, sperm parameters and biochemical markers.

Subject and design: The study involved 152 men who were distributed into three groups according to the body mass index (BMI, kg/m²): control group with normal values (18.5-24.9), preobese (25.0-29.9), and obese (≥30.0).

Materials and methods: Semen analysis included parameters: volume, sperm concentration and total count, morphology, progressive (PR) and total motility. Levels of fructose, citric acid, and zinc were measured in seminal plasma.

Statistic: The results of the studies were analyzed using StatPlus: mac (AnalystSoft Inc., version 6). The Mann-Whitney U-test was used to compare groups. Pearson's correlation coefficient was calculated. P < 0.05 was considered statistically significant.

Results: No significant differences of the semen parameters were observed between preobese and control group, except for increasing the number of abnormal spermatozoa. The obese group revealed lower concentration and total number of sperm, PR motility. BMI was negatively correlated with most semen parameters. The overweight group showed a decreasing of fructose levels and increasing of citric acid and zinc concentration, while no significant changes were observed in the obese group, except for a decreasing in fructose.

Conclusions: The present study confirms that with the growth of BMI, the sperm quality deteriorates. Based on these results, we can assume that obesity may be an injurious factor of male infertility.

Keywords: Body mass index; infertility; obesity; overweight; sperm.