摘要：Abstract Background A decreased risk of prostate cancer (PCa) has been suggested in men taking aspirin, statins and metformin, although the evidence has been conflicting. We estimated the association between prescribed medications, prostate specific antigen (PSA) levels and the risk of either any PCa or high-grade PCa. Methods This population-based cohort study included 185,667 men having a first recorded PSA test and 18,574 men having a first prostate biopsy in Stockholm County, Sweden for the period 2007–2012. Detailed clinical information including PSA levels, biopsy results, comorbidities and educational level were obtained from population-based registers. High-grade prostate cancer was defined as a Gleason score of seven or higher. Differences in PSA levels by medication status were estimated using linear regression on log PSA values. PCa risk was estimated using multivariate logistic regression. Results Compared with men who were not on medication, the PSA level at the first PSA test was lower among men using 75 mg/dose aspirin (−3.9% change in PSA concentration; 95% confidence interval (CI): −5.8 to −2.1), statin (−4.6%; 95% CI: −6.2 to −2.9), metformin (−14%; 95% CI: −17 to −12) and insulin (−16%; 95% CI: −18 to −14). Men using any statins had an increased risk of both high-grade PCa (odds ratio (OR) 1.25; 95% CI: 1.10–1.42) and PCa of any grade (OR 1.16; 95% CI 1.04–1.29). There were no significant associations between aspirin or any antidiabetic medication and the risk of PCa. Conclusion We found no protective effect of aspirin, statins or antidiabetics in terms of risk for any PCa or high-grade PCa. Use of any statins was associated with an elevated risk of being diagnosed with high-grade prostate cancer.