epidemiology

Last reviewed 01/2018

There is a significant variation of incidence between countries. A higher incidence is seen in the UK, the Faroe Islands, and Norway (1)
  • incidence also depends on race e.g. - 10.8 per 100,000 Caucasians and 0.45 Negroid children
  • a higher incidence is also recorded in
    • areas of lower population compared to more densely populated areas (2)
    • lower socioeconomic status
    • delayed skeletal age   

It occurs primarily in children aged between 5 and 12 years (2); typically between 3 and 7 years. (2)

  • more common in boys (5x) than in girls (3)
  • a benign disease is seen when diagnosed at a younger age while children diagnosed at an older age requires increased intervention and generally experience poorer outcomes (3)
  • family history in 12%
  • about 15% are bilateral (3).

Reference: