The Association between Glycemic Control and Semen Parameters

Introduction:
The prevalence of diabetes mellitus (DM) and impaired fasting glucose (IFG) is increasing worldwide. DM is known to affect the endocrine function, a crucial role player in normal spermatogenesis.

Aim:
To assess the impact of IFG and DM on seminal fluid and sperm parameters.

Materials and Methods:
A retrospective case-control study including data from semen analyses of patients undergoing fertility evaluation was conducted. Samples were collected between the years 2009-2017. Patients younger than 18 or older than 65 years, previous chemotherapy or radiotherapy or genetic abnormalities were excluded. Multivariate analysis was performed to control for confounders.

Results:
A total of 7,118 semen samples of 3,724 patients were included. Comparing DM (n=336) to IFG (n=276) and healthy patients (HP) (n=6679), the DM patients were older, with significantly higher smoking and baseline FSH levels. The BMI of DM and IFG patients was significantly increased compared to the HP group (28.8±5.4 and 29.4±6.0 vs. 25.9±6.7 respectively, p<0.001). The DM group had higher rates of low semen volume compared to the IFG and HP groups (24.1%, 18.1% and 15.3% respectively, p<0.001), asthenozoospermia (40.2%, 39.1% and 34.2% respectively, p=0.035) and teratozoospermia (65.7%, 51.5% and 25.9%, respectively, p<0.001). Using multiple logistic regression models, controlling for confounders including age, BMI and smoking status, DM but not IFG were found as independent risk factors for low seminal fluid volume and teratozoospermia.

Conclusion:
DM deteriorates semen volume and sperm morphology, resulting in possible reduced fecundity. Metabolic state improvement should be offered to the patients prior to fertility treatment.