Lower Urinary Tract Infection and Subsequent Risk of Prostate Cancer: A Nationwide Population-Based Cohort Study

PURPOSE We investigated whether lower urinary tract infection (LUTI), including cystitis or urethritis, is associated with an increased risk of developing prostate cancer (PCa), in a nationwide population-based cohort study. METHODS We identified 14,273 men newly diagnosed with LUTI (9347 with cystitis, and 4926 with urethritis) between 1998 and 2011, from the Taiwan Longitudinal Health Insurance Database 2000. Each patient was randomly frequency-matched with 4 men without LUTI, based on age and index year of diagnosis. Cox's proportional hazard regression analysis was performed to estimate the effect of LUTI on the PCa risk. RESULTS The risk of developing PCa was significantly higher in the cystitis cohort (adjusted HR = 1.46, 95% CI = 1.20-1.78) and in the urethritis cohort (adjusted HR = 1.72, 95% CI = 1.26-2.34) than in the group without LUTI. Further analyses indicated that patients with more than 5 medical visits for LUTI per year had a significantly greater risk of developing PCa. CONCLUSION We found that cystitis or urethritis may play an etiological role in the development of PCa in Taiwanese men, particularly in those with repeated medical visits for cystitis or urethritis. Further studies are warranted on the association between LUTI and PCa in other countries, particularly where the prevalence of PCa is high.