title: Perthes' disease of the hip: socioeconomic inequalities and the urban environment.
abstract: BACKGROUND
  Perthes' disease is a puzzling childhood hip disorder for which the aetiology is unknown. It is known to be associated with socioeconomic deprivation. Urban environments have also been implicated as a risk factor, however socioeconomic deprivation often occurs within urban environments and it is unclear if this association is the result of confounding. The objective of the current work was to gain a greater understanding of the influence of the urban/rural environment in Perthes' disease.
  
  
  METHODS
  This was a descriptive observational study using the Scottish Morbidity Record, based in Scotland, UK using data from 2000-2010. A total of 443 patients with a discharge diagnosis of Perthes' disease were included. Socioeconomic deprivation was determined using the Scottish Index of Multiple Deprivation, and exposure to the 'urban environment' was recorded based on the Scottish Urban-Rural Classification.
  
  
  RESULTS
  There was a strong association with socioeconomic deprivation, with rates among the most deprived quintile more than twice those of the most affluent (RR 2.1 (95% CI 1.5 to 2.9)). Urban areas had a greater rate of Perthes' disease discharges (RR 1.8 (95% CI 1.1 to 3.2)), though this was a reflection of greater deprivation in urban areas. Stratification for socioeconomic deprivation revealed similar discharge rates in urban and rural environments, suggesting that the aetiological determinants were not independently associated with urban environments.
  
  
  CONCLUSIONS
  The occurrence of Perthes' disease within urban environments is high, yet this appears to be a reflection of higher socioeconomic deprivation exposure. Disease rates appear equivalent in similarly deprived urban and non-urban areas, suggesting that the determinant is not a consequence of the urban environment.
authors.affiliation: Department of Orthopaedic Surgery, Alder Hey Childrens' Hospital, Eaton Road, Liverpool, UK. danperry@doctors.org.uk
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Perry
authors.forename: Colin E
authors.initials: CE
authors.lastname: Bruce
authors.forename: Daniel
authors.initials: D
authors.lastname: Pope
authors.forename: Peter
authors.initials: P
authors.lastname: Dangerfield
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Platt
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hall
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007873:Legg-Calve-Perthes Disease / Q000453:epidemiology*; D008297:Male; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology; D012923:Social Class; D014505:Urban Population