APH 2005, 63, 17-34:
A Belgian case control study on bladder cancer: rationale and design.
E. Kellen MD, M. Zeegers PhD, D. Lousbergh MD, A. Paulussen PhD, F. Buntinx MD PhD
Keywords: Bladder neoplasm, case-control study, risk factors, epidemiology
Previous analyses of the Limburg Cancer registry (LIKAR) indicated the existence of a geographical cluster of bladder cancer incidence, particularly transitional cell carcinomas, amongst males in the surrounding area of the Belgian cities Hasselt and Alken. In subsequent ecologic analyses no risk factors were identified which could explain the existence of this cluster. Therefore, a case-control study has been started in the province of Limburg to explore the determinants of the cluster. In the coming years, the following determinants will be investigated: socio-demographic characteristics (e.g. age, sex, socio-economic status), life style factors (smoking, alcohol and diet), occupational exposure and genetic predisposition. The research setup combines a traditional population based case-control design with a case-only design. 203 Cases, defined by a recent histological confirmed diagnosis of transitional cell carcinoma (after January 2000), have been recruited through the LIKAR registry, the pathologist and the referring urologist. Population based controls (n=380) have been selected, through simple random sampling, from the inhabitants of the province of Limburg above the age of 50. Individual data have been collected through personal (structured) interviews by two trained interviewers. Genetic polymorphisms have been determined using genomic DNA extracted from blood samples. Determinant distributions of cases have been compared with those from controls in logistic regression analyses with special emphasis on gene-environment and gene-gene interactions. This paper will introduce this study and will report on its methodology in more detail than is possible in subject specific results papers.