Updated estimates of the proportion of childhood leukaemia incidence in Great Britainthat may be caused by natural background ionising radiation

Abstract

The aetiology of childhood leukaemia remains generally unknown, although exposure tomoderate and high levels of ionising radiation, such as was experienced during the atomicbombings of Japan or from radiotherapy, is an established cause. Risk models basedprimarily upon studies of the Japanese A-bomb survivors imply that low-level exposure toionising radiation, including to ubiquitous natural background radiation, also raises the riskof childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770–6) weestimated the proportion of childhood leukaemia incidence in Great Britain attributableto natural background radiation to be about 20%. In this paper we employ thetwo sets of published leukaemia risk models used previously, but use recentlypublished revised estimates of natural background radiation doses received by thered bone marrow of British children to update the previous results. Using thenewer dosimetry we calculate that the best estimate of the proportion of cases ofchildhood leukaemia in Great Britain predicted to be attributable to this source ofexposure is 15–20%, although the uncertainty associated with certain stages in thecalculation (e.g. the nature of the transfer of risk between populations and the pertinentdose received from naturally occurring alpha-particle-emitting radionuclides)is significant. The slightly lower attributable proportions compared with thosepreviously derived by Wakeford et al (Leukaemia 2009 23 770–6) are largely due tothe lower doses (and in particular lower high LET doses) for the first year oflife.