The Copenhagen case-control study of bladder cancer. V. Review of the role of urinary-tract infection.

During the years 1979-1981, a population-based study of 388 patients with bladder cancer, including papilloma, and of 790 controls was conducted in Greater Copenhagen. No pronounced difference between cases and controls of either sex was observed for bladder infection, kidney infection or bladder stones. Women with kidney stones had a significantly elevated relative bladder cancer risk (RR = 3.7; 95% CI = 1.2-12.1); the risk for bladder cancer was also increased (RR = 1.5), although not significantly so, in women who had ever had a 'kidney disease'. A review of the existing studies in humans and in animals of the association between bladder infection and cancer reveals a need for studies to determine whether urinary-tract infections increase either the true risk for bladder tumours or only complications of early bladder cancer before a clinical diagnosis has been made.