RESUMO
OBJECTIVE: To examine the relationship between abnormal routine semen parameters and DNA damage associated with advanced paternal age and infertility by controlling for common biases contested in the current literature. MATERIALS & METHODS: Prospective study using 151 semen samples collected from men aged 18-80 at 2 visits with 1-3 months intervals. Samples were collected from both infertile and general population controls. Conventional semen parameters were measured including volume, concentration and motility. Sperm DNA damage was measured using the %DNA Fragmentation Index (%DFI) and High DNA stainability (%HDS) using Sperm Chromatin Structure Assay (SCSA). Patients were then classified according to %DFI as normal (<18), intermediate (18-27), or high (>27). RESULTS: Significant correlation between all sperm parameters was seen between both visits regardless of age. DFI had the highest correlation between both visits (R2 = 0.77). Progressive motility, total motility and %DFI were significantly affected in men ≥50 years old when compared to men <35 and men 35-49 years old (P <.001). Forty-eight percent of men with intermediate %DFI changed category on their second visit, whereas men with high and low %DFI changed category in 15% and 9%, respectively. CONCLUSION: Sperm and SCSA parameters do not change significantly between 2 visits at 1-3 months intervals in the total population and after subgrouping. Men of advanced age have poorer sperm parameters and more DNA damage. Men with initially normal or elevated %DFI are unlikely to change DNA damage category. Older men are more likely to have sperm parameters and DNA damage vary on repeat semen analysis compared to younger men.
