Early exposure to infection and childhood leukaemia
Gilham et al’s findings(1) are a significant contribution to the
understanding of the aetiology of childhood leukaemia and support earlier
research carried out in this field including a study based on the same
UKCCS dataset examining population mixing as a proxy for infectious
exposure and childhood cancer (2). This related study lends further
weight to their findings as it uses a different and independent exposure
metric but produces analogous results.
Our group has also investigated the effect of early social contact in
relation to childhood diabetes (3) and population mixing in relation to
childhood cancer (4), and parallels between the two conditions which seem
to share some aspects of a common aetiology.(5). All of these studies
point to similar results. Exactly what type of infection or group of
infections are important in improving immunological competence and the
biological mechanisms by which these operate are yet to be established.
Striking the right balance between protecting our children from damaging
or life threatening infections whilst exposing them to a ‘sufficient dose’
of milder infections to prime their immune systems, has far-reaching
social and behavioural connotations.
1 Gilham C, Peto J, Simpson J, Roman E, Eden TOB, Greaves MF,
Alexander FE, for the UKCCS Investigators. Day care in infancy and risk
of childhood acute lymphoblastic leukaemia: findings from UK case-control
study. BMJ, doi:10.1136/bmj.38428.521042.8F (published 22 April 2005)
2 Law GR, Parslow RC, Roman E. Childhood cancer and population
mixing. Am J Epidemiol 2003;158:328-36
3 McKinney PA, Okasha M, Parslow RC, Law GR, Gurney KA, Williams DRR,
Bodansky HJ. Early social mixing and childhood type 1 diabetes: a case-
control study in Yorkshire, UK. Diabet Med 2000;17(1):236-242
4 Parslow RC, Law GR, Feltbower R, Kinsey SE, McKinney PA.
Population mixing, childhood leukaemia, CNS tumours and other childhood
cancers in Yorkshire. Eur J Cancer 2002; 38:2033–2040.
5 Feltbower RG, Manda SOM, Gilthorpe MS, Greaves MF, Parslow RC,
Bodansky HJ, Kinsey SE, McKinney PA. Small area similarities in the
epidemiology of childhood acute lymphoblastic leukaemia and Type 1
diabetes: a Bayesian approach. Am J Epidemiol 2005; In press.
Competing interests: No competing interests