title: Risk of testicular cancer in men with abnormal semen characteristics: cohort study.
abstract: OBJECTIVE
  To explore the associations between semen characteristics and subsequent risk of testicular cancer.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  32 442 men who had a semen analysis done at the Sperm Analysis Laboratory in Copenhagen during 1963-95.
  
  
  METHODS
  Standardised incidence ratios of testicular cancer compared with total population of Danish men.
  
  
  RESULTS
  Men in couples with fertility problems were more likely to develop testicular cancer than other men (89 cases, standardised incidence ratio 1.6; 95% confidence interval 1.3 to 1.9). The risk was relatively constant with increasing time between semen analysis and cancer diagnosis. Analysis according to specific semen characteristics showed that low semen concentration (standardised incidence ratio 2.3), poor motility of the spermatozoa (2.5), and high proportion of morphologically abnormal spermatozoa (3.0) were all associated with an increased risk of testicular cancer. The only other cancer group that showed increased incidence was "peritoneum and other digestive organs" (six cases; 3.7, 1.3 to 8.0). Of these, two cases were probably and two cases were possibly extragonadal germ cell tumours.
  
  
  CONCLUSIONS
  The results point towards the existence of common aetiological factors for low semen quality and testicular cancer. Low semen quality may also be associated with increased incidence of extragonadal germ cell tumours.
authors.affiliation: Centre for Research in Health and Social Statistics, Danish National Research Foundation, DK-2100 Copenhagen, Denmark.
authors.forename: R
authors.initials: R
authors.lastname: Jacobsen
authors.forename: E
authors.initials: E
authors.lastname: Bostofte
authors.forename: G
authors.initials: G
authors.lastname: Engholm
authors.forename: J
authors.initials: J
authors.lastname: Hansen
authors.forename: J H
authors.initials: JH
authors.lastname: Olsen
authors.forename: N E
authors.initials: NE
authors.lastname: Skakkebaek
authors.forename: H
authors.initials: H
authors.lastname: Moller
mesh_terms: D000328:Adult; D016001:Confidence Intervals; D004067:Digestive System Neoplasms / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007248:Infertility, Male / Q000150:complications* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009373:Neoplasms, Germ Cell and Embryonal / Q000453:epidemiology / Q000209:etiology; D010534:Peritoneal Neoplasms / Q000453:epidemiology; D012189:Retrospective Studies; D012306:Risk; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa; D013736:Testicular Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology