KLK3 and prostate cancer: Our results are in line with a previous population-based observational cohort (Prostate Cancer Database Sweden) [27] which also found that at PCa diagnosis, patients with more comorbidities (using as we did, the Charlson comorbidity index) tended to be older than those without any comorbidities, and the median PSA level at diagnosis was also higher in the comorbid group compared to the group with no comorbidities.