Indoor residential radon exposure and risk of childhood acute myeloid leukaemia

Exposure to radon has been identified as a risk factor for lung cancer in u ranium miners, but evidence of adverse health effects due to indoor radon e xposure is inconsistent. Ecological studies have suggested a correlation be tween indoor radon levels and leukaemia incidence. We evaluated the risk as sociated with indoor residential radon exposure within a larger interview-b ased case-control study of risk factors for childhood acute myeloid leukaem ia (AML). A total of 173 cases and 254 controls met the eligibility criteri a, and information was collected through telephone interviews with parents and analysis of alpha-track radon detectors placed in the home for a period of 1 year. No association was observed between radon exposure and risk of AML, with adjusted odds ratios of 1.2 (95% confidence interval (CI) 0.7-1.8 ) for 37-100 Bq m(-3) and 1.1 (95% Cl 0.6-2.0) for > 100 Bq m(-3) compared with < 37 Bq m(-3). Although there was an inverse association between radon level and AML risk among children < 2 years at diagnosis, among children g reater than or equal to 2 years, AML risk was increased among those with hi gher radon exposure. The observed association after age 2 is most likely du e to chance. Overall, there was no association between residential radon an d risk of childhood AML. (C) 1999 Cancer Research Campaign.