England-wide case-control study of the association of recurrent urinary tract infections with bladder cancer risk

Around 30-40% of people with bladder cancer (BC) in England present with symptoms or diagnosis of urinary tract infection (UTI) in the year before BC diagnosis. A nationwide retrospective case-control study in England investigated the effect of recurrent UTIs on the likelihood of BC. The study included adult patients with a BC diagnosis between 1998 and 2018 who had at least on UTI before diagnosis (n=17,584) who were matched (1:5) for age, sex, and general practice to 87,920 controls without BC. A dose-relationship between recurrent UTI and BC risk was seen in the first 6 months only, with the largest effect for five or more UTIs at 0-6 months (aOR 13.05; 95% CI 11.60-14.68); patients with five or more UTIs had around 2.5 times higher odds than those with three UTIs in the same interval (4.95; 4.51-5.43). Associations attenuated with increasing time from the most recent UTI before BC diagnosis. The authors conclude that recurrent UTIs within 6 months were a strong signal of BC risk.