However, our previous research in the same study population has clearly demonstrated that the presence of MetS was independently associated with an 11.3% decline in serum PSA levels compared with subjects without MetS in the general population, and the increasing number of MetS components was significantly and linearly associated with declining in serum PSA levels52; thus, using this cut-off value of PSA as an simple indicator of clinical BPH may underestimated the actual incidence, especially in subjects with MetS. This evidence concerns the gene KLK3 and benign prostatic hyperplasia.