epidemiology

Last reviewed 01/2018

  • CLL is the commonest type of leukaemia in the western world
    • the annual incidence rate in this part of world is estimated to be of 4 per 100.000 (1)
    • it accounts for 40% of all cases of leukaemias in people over the age of 65 years
    • it is 20-30 times more commoner in Europe, Australasia and North American white and black populations than in India, China and Japan (1)
  • less than 5% of CLL are T cell type
  • disease is diagnosed most commonly in the elderly
    • it is extremely rare before the age of 30 years (1)
    • the median age at diagnosis is 69 years with 80% of patients diagnosed more than 60 years of age
    • the incidence increases to >30 per 100,000 per year at age of more than 80 years (2)
  • men are affected twice as commonly as women

The role of environmental factors is unclear. Genetic factors may be involved.

  • there may be some overlap between CLL and the leukaemic phase of lymphomas.

Reference: