title: High prevalence of isolated sperm DNA damage in infertile men with advanced paternal age.
abstract: BACKGROUND
  Sperm DNA damage is associated with male infertility, lower pregnancy rates and pregnancy loss.
  
  
  OBJECTIVE
  The primary aim of our study was to evaluate the prevalence of sperm DNA damage in younger and older men with normozoospermia.
  
  
  METHODS
  We obtained semen from 277 consecutive non-azoospermic men presenting for sperm DNA testing.
  
  
  METHODS
  The main outcome measures included sperm % DNA fragmentation index (%DFI, using sperm chromatin structure assay), sperm concentration, motility and morphology, and, paternal age.
  
  
  CONCLUSIONS
  Sperm % DFI was positively correlated with paternal age (r = 0.20, P < 0.001) and inversely correlated % progressive motility (r = -0.16, P = 0.01). Sperm %DFI was significantly higher in older (≥40 years) compared to younger (<40 years) normozoospermic men (17 ± 13 vs. 12 ± 8, respectively P = 0.008), whereas, sperm concentration, progressive motility and morphology were not significantly different in these two groups. Moreover, the prevalence of high levels of sperm DNA damage (>30 % DFI) was significantly higher in older compared to younger normozoospermic men (17 % vs. 3 %, respectively, P < 0.001).
  
  
  CONCLUSIONS
  The data indicate that a conventional semen analysis can often fail to detect a defect in spermatogenesis (high %DFI) in older men and suggest that infertile couples with advanced paternal age, including those with normal semen parameters, should consider sperm DNA testing as part of the couple evaluation.
authors.affiliation: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
authors.forename: Mausumi
authors.initials: M
authors.lastname: Das
authors.forename: Naif
authors.initials: N
authors.lastname: Al-Hathal
authors.forename: Maria
authors.initials: M
authors.lastname: San-Gabriel
authors.forename: Simon
authors.initials: S
authors.lastname: Phillips
authors.forename: Isaac-Jacques
authors.initials: IJ
authors.lastname: Kadoch
authors.forename: Francois
authors.initials: F
authors.lastname: Bissonnette
authors.forename: Hananel
authors.initials: H
authors.lastname: Holzer
authors.forename: Armand
authors.initials: A
authors.lastname: Zini
mesh_terms: D000328:Adult; D004249:DNA Damage / Q000235:genetics*; D053938:DNA Fragmentation; D005260:Female; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010331:Paternal Age; D011003:Ploidies; D011247:Pregnancy; D055101:Semen Analysis; D013076:Sperm Count; D013091:Spermatogenesis / Q000235:genetics*; D013094:Spermatozoa / Q000473:pathology*