(i) older men have increased sperm DNA damage associated with alkali-labile sites or single-strand DNA breaks ...

Hum Reprod. 2007 Jan;22(1):180-7. Epub 2006 Oct 19. Links
The effects of male age on sperm DNA damage in healthy non-smokers.Schmid TE, Eskenazi B, Baumgartner A, Marchetti F, Young S, Weldon R, Anderson D, Wyrobek AJ.
Lawrence Livermore National Laboratory, Livermore, CA, USA.

BACKGROUND: The trend for men to have children at older age raises concerns that advancing age may increase the production of genetically defective sperm, increasing the risks of transmitting germ-line mutations. METHODS: We investigated the associations between male age and sperm DNA damage and the influence of several lifestyle factors in a healthy non-clinical group of 80 non-smokers (mean age: 46.4 years, range: 22-80 years) with no known fertility problems using the sperm Comet analyses. RESULTS: The average percentage of DNA that migrated out of the sperm nucleus under alkaline electrophoresis increased with age (0.18% per year, P = 0.006), but there was no age association for damage measured under neutral conditions (P = 0.7). Men who consumed >3 cups coffee per day had approximately 20% higher percentage tail DNA under neutral but not alkaline conditions compared with men who consumed no caffeine (P = 0.005). CONCLUSIONS: Our findings indicate that (i) older men have increased sperm DNA damage associated with alkali-labile sites or single-strand DNA breaks and (ii) independent of age, men with substantial daily caffeine consumption have increased sperm DNA damage associated with double-strand DNA breaks. DNA damage in sperm can be converted to chromosomal aberrations and gene mutations after fertilization, increasing the risks of developmental defects and genetic diseases among offspring.

PMID: 17053003 [PubMed - indexed for MEDLINE]