Abstract
There is a general belief that the clustering of childhood leukaemia is a widespread
phenomenon and that it provides evidence for appreciable environmental influence on
the incidence of the disease. We discuss this issue critically, identifying different
kinds of clustering and their possible aetiological mechanisms and examining some
analyses of British data. We argue that, in some cases, analyses have been used which
lead to dubious conclusions, and that, allowing for multiple testing and anecdotal
reporting, the total evidence for clustering is at best weak.
Keywords
Clustering - Childhood Leukaemia - Geographical Epidemiology