Epidemiology of sperm DNA fragmentation in a retrospective cohort of 1,191 men

The scientific and clinical communities now recognize that sperm DNA integrity is crucial for successful fertilization, good embryo development and offspring quality of life. Despite the apparent unanimity, this criterion is rarely evaluated in clinical practice. We evaluated the sperm DNA fragmentation index (DFI) of nearly 1,200 sperm samples and its connections based on the patient's age, BMI, season of sperm collection, geographical location, medical history and addictive behaviors. A cohort of 1,503 patients who were referred to the Royan Institute between July 2018 and March 2020 was examined. Only 1,191 patient records with demographic data, complete semen analysis and DFI measurements were included in the final cohort. Documents were classified, incorporated into statistical models and analyzed. The results confirmed previous findings that sperm DFI was significantly higher in aging men. Sperm DFI and high DNA stainability (HDS) levels were significantly higher in spring and summer samples than in those of other seasons. No correlation was found between semen DFI and patient BMI, although the study cohort was significantly overweight. Contrary to what might be expected, we observed that sperm DFI was higher in rural than in urban patients. Intriguingly, epileptic patients exhibited significantly higher sperm DFI levels. Age is the factor that is most strongly associated with sperm DFI levels. Our analysis of 1,191 samples indicates that between the ages of 19 and 59, sperm DFI increases by an average of 2% each year. Intriguingly, from an epidemiological perspective, the warm season (spring/summer) is associated with higher sperm DFI in the study population, possibly due to the deleterious effect of temperature on sperm quality. Some neurological diseases, such as epilepsy, are associated with decreased sperm DNA integrity. This observation could be related to the iatrogenic effects of associated therapies. In the study cohort, BMI did not appear to be correlated with DFI. This article is protected by copyright. All rights reserved.