Childhood leukemia and proximity to nuclear power plants: A systematic review and meta-analysis

• Previous studies show unclear results of nuclear power plants (NPPs) and childhood leukemia.
• Study design features, including metrics of distance, can affect resulting risk estimates.
• Studies of children living <25 km of NPPs indicated little evidence of childhood leukemia risks.
• Studies of children <5 years of age living <5 km of NPPs, presented some evidence of increased risks.
• Improved monitoring and exposure assessment are needed of populations surrounding NPPs.

ObjectiveTo evaluate the association between childhood leukemia and residential proximity to nuclear power plants (NPP).MethodsWe performed a systematic review by searching the MEDLINE database for published studies of childhood leukemia incidence and proximity to NPP. The primary analysis included children <15 years of age living within 25 km of a NPP, and the secondary analysis focused exposure of children <5 years of age living within 5 km of such facilities.ResultsA meta-analysis including eight studies (1,665 cases) of childhood leukemia within 25 km of NPPs produced a pooled estimate of 1.00 (95% confidence interval (CI) = 0.95–1.05). A secondary analysis of a subset of three case-control studies (53 cases) examining the risk in children <5 years of age within 5 km of a NPP produced a meta-estimate of 1.45 (95% CI = 0.74–2.86), and an analysis of the same parameters using four studies (76 cases) from ecological/cohort studies generated a significantly elevated pooled estimate of 1.33 (95% CI = 1.05–1.68).ConclusionMeta-estimates for ecological/cohort and case-control studies did not provide evidence of an increase in leukemia incidence in children <15 years of age living <25 km of a NPP. A subset of studies including children <5 years of age living <5 km from a NPP produced significantly elevated estimates for ecological/cohort studies. Continuing to undertake large-scale studies of populations surrounding nuclear facilities is encouraged to refine potential risks and better understand methodological nuances.