title: East-West gradient in semen quality in the Nordic-Baltic area: a study of men from the general population in Denmark, Norway, Estonia and Finland.
abstract: BACKGROUND
  Denmark and Norway have a three-fold higher incidence of testicular cancer than Estonia and Finland. Groups of young men from Denmark, Norway, Finland and Estonia were investigated to elucidate whether semen parameters and other related parameters follow a gradient between these countries, as does the gradient in incidence of testicular cancer.
  
  
  METHODS
  In total, 968 young men from the general population in these four countries were investigated according to the same protocol. Possible confounders were evaluated, and included in the statistical analysis when appropriate. Inter-laboratory differences in assessment of sperm concentrations were controlled by an external quality control programme and morphology assessment was centralized to one person.
  
  
  RESULTS
  The Finnish and Estonian men had an adjusted median sperm concentration of 54 and 57 x 10(6)/ml, respectively and the Norwegian and Danish men 41 x 10(6)/ml. The corresponding total sperm counts were 185, 174, 133 and 144 x 10(6). The frequency of normal sperm in men from Finland was 8.9%, Estonia 9.2%, Norway 6.9% and Denmark 6.4%. Within all four groups of men, a relationship between increasing levels of inhibin-B and increasing sperm counts was observed. However, inhibin-B levels were not predictive of sperm count differences between countries.
  
  
  CONCLUSIONS
  It is believed that the men examined were representative of the normal population of young men in all four countries as they were recruited from groups attending a compulsory medical examination, and not selected for known fertility or semen quality. Moreover, the majority of participants had no prior knowledge of their fertility potential. It appears that an east-west gradient exists in the Nordic-Baltic area with regard to semen parameters, this being in parallel with the incidences of testicular cancer. Further investigations are required to determine whether these findings are due to genetic differences, to different environments, or perhaps to a combination of both factors.
authors.affiliation: Department of Growth and Reproduction, Rigshospitalet, The Juliane Marie Centre, Copenhagen, Denmark. njcph@rh.dk
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Carlsen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Nermoen
authors.forename: Margus
authors.initials: M
authors.lastname: Punab
authors.forename: Jyrki
authors.initials: J
authors.lastname: Suominen
authors.forename: Anne-Grethe
authors.initials: AG
authors.lastname: Andersen
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Andersson
authors.forename: Trine B
authors.initials: TB
authors.lastname: Haugen
authors.forename: Antero
authors.initials: A
authors.lastname: Horte
authors.forename: Tina Kold
authors.initials: TK
authors.lastname: Jensen
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Magnus
authors.forename: Jørgen Holm
authors.initials: JH
authors.lastname: Petersen
authors.forename: Matti
authors.initials: M
authors.lastname: Vierula
authors.forename: Jorma
authors.initials: J
authors.lastname: Toppari
authors.forename: Niels E
authors.initials: NE
authors.lastname: Skakkebaek
mesh_terms: D000328:Adult; D003710:Demography; D003718:Denmark; D004957:Estonia; D005387:Finland; D006801:Humans; D007265:Inhibins / Q000097:blood; D008297:Male; D009664:Norway; D012661:Semen / Q000502:physiology*; D013076:Sperm Count
chemical_list: C422364:inhibin B; D007265:Inhibins