Geographical and ecological analyses of childhood Wilms' tumours and soft-tissue sarcomas in North West England.

The aim of this paper was to study the geographical distribution of Wilms' tumours (WT) and soft-tissue sarcomas (STS) for 0-14 year olds included in a population-based registry from North West England during 1976-2000. Standardised morbidity ratios (SMRs) were calculated. Relationships between incidence rates and small area (ward) population density, ethnic composition, deprivation index and urban-rural status were examined using Poisson regression. There was a non-linear relationship between WT incidence and population density (P=0.008), with a higher incidence associated with wards with low deprivation scores (P=0.02); and which included a greater proportion of whites (P=0.01). For STS, a higher incidence was associated with wards with low deprivation scores (P=0.04); and which were 'more rural/less urban' (P=0.03). These results are consistent with a role for localised environmental exposures, in combination with lifestyle factors, in the aetiology of WT. For STS, there is some evidence for the involvement of environmental and/or lifestyle factors.