Background and aims: Diabetes mellitus may play a negative effect on male fertility. The aim of the present study is to evaluate the association of glucose variability with semen quality in young adults with type 1 diabetes (T1DM) in treatment with continuous glucose monitoring (CGM) systems with high or low glycemic variability (GV). Materials and methods: This cross-sectional study included sexually active young adults with T1DM on intensive insulin treatment, using CGM systems. CGM-related metrics of 14 days before the visit, including the percentage of time in range of normo-glycemia (TIR), time above range (TAR 1 and TAR 2), time below range (TBR1 and TBR2), coefficient of variation for glucose variability (CV) and glucose management indicator (GMI), were collected from web-based platforms. Participants were divided in high GV or low GV group, according to a CV ≥36% and <36% respectively. Results: The study population included 88 men with mean age of 25.8 years and mean diabetes duration of 15.3 years. Patients with high GV showed lower semen volume [CV≥36% vs CV<36% group, median (IQR), 2.5 (2.2, 2.6) vs 2.8 (2.5, 4.3) mL, p<0.001], lower sperm total count [44 (30, 53) vs 58 (50, 94) mil/ejaculate, p<0.001], lower total motility [45 (35, 45) vs 45 (45, 50)%, p=0.001], higher absent motility [55 (55, 65) vs 50 (50, 55)%, p=0.001], lower percentage of typical cell morphology [5 (5, 5) vs 6 (5, 6)%, p=0.014] as compared with individuals with low GV. Based on multivariate logistic regression analysis, age (OR 0.719, 95%CI 0.601, 0.859, p<0.001) and HbA1c (OR 3.898, 95%CI 1.947, 7.803, p<0.001) resulted as the only independent predictors of normozoospermia. Conclusions: Individuals with T1DM and high glycemic variability showed worse semen parameters, including ejaculate volume, spermatozoa total count and progressive motility and percentage of cell with typical morphology, than patients with low glycemic variability.
