Background and Aim: Prostate cancer is one of the most prevalent type of cancer and the second cause of death among American men. Its prevalence has a direct relationship with increasing age. The present study was carried out to determine the level of prostate specific antigen (PSA) in Birjandi males aged between 40 and 80 years.

  Material and Methods: In this prospective study, out of 628 healthy Birjandi males, 200 men who did not have any symptoms of prostate cancer were selected from different inner-city areas through cluster sampling during a period of two years (May 2003-June 2005). After the population was approved to have the necessary criteria to be included in the study, their PSA level was measured and its mean in four age groups 40-49, 50-59, 60-69, and 70-79 years was calculated. To rule out prostate cancer cases urinalysis test was done and the subjects underwent DRE (digital rectal examination), and prostate sonography. In order to determine mean difference among the four groups one-way variance analysis test and to determine "PSA" PSA Assay and Tandem-R kits were utilized.

  Results: Mean and standard deviation of PSA in the 40-49, 50-59, 60-69, and 70-79 year groups was 0.6±0.04, 0.8±0.55, 1±0.09, and 1.4±1.57, respectively. Thus, there was a significant difference between mean level of PSA among the four groups (P<0.05). In a healthy sixty-year old male, e.g., yearly PSA increase is about 32% (0.04 ng/mL per year). Besides, prostate volume has a direct relationship to client's age while PSA density has a weak relationship to age.

  Conclusion: With respect to the findings of the study, it could be confirmed that PSA level increases in healthy males while they grow older and because of its natural range at any age it can be used as a measure to screen for prostate cancer.