risk of prostate cancer [adjusted hazard ratios (aHRs), 1.46; 95% confidence intervals (CI), 1.11-1.91]. Additionally, individuals who used four or more antibiotic classes had a higher risk of prostate cancer (aHR, 1.18; 95% CI, 1.07-1.30) than those who did not use antibiotics. 5 This study has some limitations. First, it did not consider antibiotic use after 2007. Second, several factors might have influenced the results, including different washout periods, index dates, and populations with health examinations. Nevertheless, this study reveals new link between prolonged antibiotic use and prostate cancer risk among the Asian population.