title: Socio-occupational class, region of birth and maternal age: influence on time to detection of cryptorchidism (undescended testes): a Danish nationwide register study.
abstract: BACKGROUND
  Cryptorchidism (undescended testes) is associated with poor male fertility, but can be alleviated and fertility preserved to some degree by early detection and treatment. Here we assess the influence of socio-occupational class, geographical region, maternal age and birth cohort on time to detection and correction of cryptorchidism.
  
  
  METHODS
  All boys born in Denmark, 1981 to 1987 or 1988 to 1994, with a diagnosis of cryptorchidism were identified in nationwide registers. The boys were followed for a diagnosis until their 16th birthday. The age at first diagnosis was noted and used as proxy for time to detection of cryptorchidism. Parental employment in the calendar year preceding birth was grouped into one of five socio-occupational classes. Geographical region was defined by place of birth in one of 15 Danish counties. Detection rate ratios of cryptorchidism were analyzed as a function of parental socio-occupational group, county, maternal age and birth cohort by use of Poisson regression.
  
  
  RESULTS
  Some 6,059 boys in the early and 5,947 boys in the late cohort received a diagnosis of cryptorchidism. Time to detection was independent of parental socio-occupational group and maternal age but differed slightly between geographical regions. A similar pattern was obtained for surgical correction after a diagnosis. Age at diagnosis decreased by 2.7 years from the early to the late cohort.
  
  
  CONCLUSIONS
  These results indicate that childhood socio-occupational inequality in detection and correction of cryptorchidism would play a negligible role in male infertility in a life course perspective. Geographical region may have exerted some influence, especially for the oldest cohort.
authors.affiliation: The National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen, Denmark. ksh@nrcwe.dk.
authors.forename: Karin Sørig
authors.initials: KS
authors.lastname: Hougaard
authors.forename: Ann Dyreborg
authors.initials: AD
authors.lastname: Larsen
authors.forename: Harald
authors.initials: H
authors.lastname: Hannerz
authors.forename: Anne-Marie Nybo
authors.initials: AM
authors.lastname: Andersen
authors.forename: Kristian Tore
authors.initials: KT
authors.lastname: Jørgensen
authors.forename: Gunnar Vase
authors.initials: GV
authors.lastname: Toft
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Bonde
authors.forename: Morten Søndergaard
authors.initials: MS
authors.lastname: Jensen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003456:Cryptorchidism / Q000175:diagnosis* / Q000453:epidemiology*; D003718:Denmark / Q000453:epidemiology; D042241:Early Diagnosis; D004651:Employment / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors; D062211:Spatio-Temporal Analysis; D013997:Time Factors; D055815:Young Adult