Geographical clustering of acute adult leukaemia in the East Anglian region of the United Kingdom: a registry-based analysis.

An ecological analysis by Alexander et al observed a small but significant excess of leukaemia excluding chronic lymphoid leukaemia in estuarine wards (relative risk=1.12, 95%CI 1.01, 1.25). This analysis was confined to cases diagnosed during 1984–1986. Using regional leukaemia incidence data for 1981– 1994, we performed a clustering study based on postcode districts of address at diagnosis to test this hypothesis further. We did not have population denominator data by postcode district, age, sex, and calendar year for the study period. We therefore adopted a case-control approach within the East Anglian (EA) cancer registry, equivalent to proportional incidence analyses.