KLK3 and prostate cancer: Their results showed that compared with men who had low CRF (< 6 METs), those with high CRF (≥ 12 METs) had a higher risk of prostate-specific antigen (PSA) screening (incident rate ratio = 1.29, 95% CI, 1.25–1.33), higher prostate cancer incidence in men aged > 55 years (HR = 1.80, 95% CI, 1.27–2.54), and 60% lower risk of prostate cancer mortality (HR = 0.40, 95% CI, 0.19–0.86) [83].