title: Oxidative DNA damage in human sperm influences time to pregnancy.
abstract: BACKGROUND
  Oxidative stress and related DNA damage in human sperm may be important for fecundity and pregnancy outcome.
  
  
  METHODS
  We studied the level of oxidative DNA damage in terms of 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) in sperm DNA among 225 first-pregnancy planners. Over the six menstrual cycle follow-up time, after cessation of contraception, 135 pregnancies were conceived.
  
  
  RESULTS
  The likelihood of pregnancy occurring in a single menstrual cycle was inversely associated with the 8-oxodG level (P < 0.01). The odds ratio of pregnancy in each of the first three or all six follow-up menstrual cycles was 0.42 (0.23-0.78; 95% CI) and 0.61 (0.36-0.91) per unit increase in the log 8-oxodG/100 000 dG ratio after adjustment for potential confounders, (including sperm concentration) respectively. The intra-individual coefficient of variation of 8-oxodG in 2-6 monthly repeated sperm samples from 116 men was 19% for the 8-oxodG/dG ratio, whereas the inter-individual coefficient of variation was 49%. The 8-oxodG level was not significantly associated with smoking, consumption of alcohol or caffeine, exposure to welding fumes or the plasma levels of sex hormones.
  
  
  CONCLUSIONS
  The data suggest that oxidative damage to sperm DNA influences fecundity and the level of damage is relatively constant within an individual and not influenced by smoking.
authors.affiliation: Institute of Public Health, University of Copenhagen, Department of Growth and Reproduction, The National University Hospital, Denmark. s.loft@pubhealth.ku.dk
authors.forename: Steffen
authors.initials: S
authors.lastname: Loft
authors.forename: Tina
authors.initials: T
authors.lastname: Kold-Jensen
authors.forename: Niels Henrik
authors.initials: NH
authors.lastname: Hjollund
authors.forename: Aleksander
authors.initials: A
authors.lastname: Giwercman
authors.forename: Jesper
authors.initials: J
authors.lastname: Gyllemborg
authors.forename: Erik
authors.initials: E
authors.lastname: Ernst
authors.forename: Jørn
authors.initials: J
authors.lastname: Olsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheike
authors.forename: Henrik Enghusen
authors.initials: HE
authors.lastname: Poulsen
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Bonde
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000428:Alcohol Drinking; D002110:Caffeine / Q000008:administration & dosage; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000032:analysis; D005260:Female; D005298:Fertility; D006801:Humans; D008297:Male; D008597:Menstrual Cycle; D016273:Occupational Exposure; D016017:Odds Ratio; D010084:Oxidation-Reduction; D011247:Pregnancy; D012044:Regression Analysis; D012907:Smoking / Q000009:adverse effects; D013076:Sperm Count; D013094:Spermatozoa / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002110:Caffeine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine