Are coffee and tea consumption associated with urinary tract cancer risk?
The literature was searched using MEDLINE, Cancerlit and Current Contents until 2000. All languages were included and bibliographies of identified papers were then reviewed. To be included, papers had to provide sufficient information to perform a summary odds ratio. Thirty-four case-control studies and three cohort studies were identified. The majority of case-control studies were either population-based (12) or hospital-based (18). Information on tea and coffee consumption was obtained by interview in the majority of studies, with a few (five) using questionnaires. All but three studies either included all neoplasms of the urinary tract as cases (of which more than 90% were found to involve bladder cancer) or selected bladder carcinomas only. Most studies used histologically confirmed cases with urothelial cell cancer.