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Effect of population mixing and socioeconomic status in England and Wales, 1979–85, on lymphoblastic leukaemia in children

BMJ 1996; 313 doi: (Published 23 November 1996) Cite this as: BMJ 1996;313:1297
  1. C A Stiller, epidemiologista,
  2. P J Boyle, lecturerb
  1. a Childhood Cancer Research Group, University of Oxford, Oxford OX2 6HJ
  2. b School of Geography, University of Leeds, Leeds LS2 9JT
  1. Correspondence to: Mr Stiller.
  • Accepted 24 September 1996


Objectives: To examine the effects of migration, diversity of migrant origins, commuting, and socioeconomic status on the incidence of acute lymphoblastic leukaemia in childhood.

Design: Poisson regression analysis of incidence rates in relation to the variables of interest.

Setting: The 403 county districts of England and Wales during 1979–85.

Subjects: Children aged under 15 years.

Results: There were significant trends in the incidence of lymphoblastic leukaemia at ages 0–4 and 5–9 years with the proportion of children in a district who had recently entered the district. While there was no consistent relation between the proportion of recent incomers in the total population of a district and its incidence rate, the combination of higher migration with greater diversity of origins or distance moved was associated with higher incidence in both age groups. Incidence increased significantly at age 0–4 with the level of employment in a district and at age 5–9 with the proportion of households with access to a car. No significant trends were found with commuting.

Conclusions: The results for level of child migration and diversity of total migration provide evidence of an effect of population mixing on the incidence of childhood leukaemia which is not restricted to areas experiencing the most extreme levels of mixing.

Key messages

  • Population mixing even at relatively low levels may be important in the aetiology of childhood leukaemia

  • The results provide further epidemiological evi- dence that childhood leukaemia might be a rare response to infection

  • Previous studies finding increased incidence in more affluent areas may have been indirectly observing a population mixing effect


  • Funding The Childhood Cancer Research Group is supported by the Department of Health and the Scottish Home and Health Department.

  • Conflict of interest None.

  • Accepted 24 September 1996
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