Relationship between human semen parameters and deoxyribonucleic acid damage assessed by the neutral comet assay

Abstract

Objective To explore the association between semen parameters and sperm DNA damage. Design Cross-sectional. Setting Andrology clinic. Patient(s) Two hundred fifty-seven men undergoing infertility assessment. Intervention(s) None. Main outcome measure(s) Sperm concentration and motility were measured using computer-assisted sperm analysis; morphology was scored using the strict criteria. The neutral comet assay was used to measure sperm DNA damage. Comet assay parameters included comet extent, percent DNA in the comet tail, and tail distributed moment, an integrated measure of length and intensity. We also scored cells that were too long to measure (>300 microm), which we referred to as cells with high DNA damage. Result(s) Men older than 35 years had a statistically significant increase in the number of cells with high DNA damage as compared with younger men. In age-adjusted regression analyses, the most consistent associations were found between semen parameters and the number of cells with high DNA damage. For an interquartile range change in the number of cells with high DNA damage, sperm concentration declined 14.2 x 10(6)/mL, motility declined 4.3%, and morphology declined 0.5%. Comet extent and percent DNA in the comet tail were also associated with a decline in sperm concentration and motility, respectively. Conclusion(s) Although there were associations between semen and comet assay parameters, their magnitudes were weak, suggesting that the comet assay provides addit…