Hughes AM et al. (2007) Allergy and risk of childhood leukaemia: results from the UKCCS. Int J Cancer 121: 819–824

Many studies have reported an inverse association between childhood leukemia and preceding history of allergy; however, the associations between specific allergy types and development of leukemia in children remain unclear. Recently, the United Kingdom Childhood Cancer Study group reported that children with a history of eczema or hayfever have a reduced risk of developing acute lymphoblastic leukemia (ALL).

The study recruited 839 individuals aged 14 years or younger who were diagnosed between 1991 and 1996 with either ALL (n = 720) or acute myeloid leukemia (n = 101), and 1,337 controls matched for age and sex. At least one allergy was diagnosed in more than one-third of cases and controls. A history of definite eczema significantly reduced the risk of developing ALL (odds ratio [OR] 0.70, 95% CI 0.51–0.97), as did a history of definite hayfever (OR 0.47, 95% CI 0.26–0.85). The risk of developing common ALL was also reduced in those children with a history of eczema or hayfever (OR 0.68, 95% CI 0.48–0.98 and OR 0.62, 95% CI 0.33–1.16, respectively). There was no association between a history of asthma and development of ALL. Moreover, none of the allergy types studied was associated with acute myeloid leukemia. The ability to detect such an association was, however, limited because of the small sample size.

This study showed an inverse relationship between childhood leukemia and preceding history of certain types of allergy, confirming the hypothesis that immune dysfunction might correlate with the development of childhood hematological malignancies.