1. ¹Department of Epidemiology and Public Health, School of Medicine and Dentistry, The Queen's University of Belfast, Belfast, UK
2. ²Cancer Epidemiology and Prevention Research Group, The Queen's University of Belfast, Belfast, UK
3. ³Paediatric Epidemiology Group, Centre for Epidemiology and Biostatistics, University of Leeds, UK

Correspondence: Dr CR Cardwell, Department of Epidemiology and Public Health, The Queen's University of Belfast, Grosvenor Road, Belfast BT12 6BJ, UK. E-mail: c.cardwell@qub.ac.uk

Received 11 June 2008; Revised 29 August 2008; Accepted 8 September 2008; Published online 30 September 2008.

Abstract

We investigated infections in early life (diagnosed in general practice) and subsequent risk of childhood leukaemia in the UK General Practice Research Database (GPRD). All children born at GPRD practices and subsequently diagnosed with leukaemia were identified as cases and were individually matched (on year of birth, sex and practice) to up to 20 controls. The final analysis included 162 leukaemia cases and 2215 matched controls. Conditional logistic regression demonstrated no evidence that children with one or more recorded infection in the first year of life had a reduced risk of leukaemia (OR=1.05, 95%CI 0.69, 1.59; P=0.83) or acute lymphoblastic leukaemia (ALL; OR=1.05, 95%CI 0.64–1.74; P=0.84). Our study provides no support for the Greaves hypothesis, which proposes that reduced or delayed exposure to infections in early life increases the risk of childhood ALL.