Serum prostate-specific antigen in a community-based population of healthy Japanese men: lower values than for similarly aged white men.

OBJECTIVE

To determine whether the age-specific reference ranges for serum prostate-specific antigen (PSA) concentration generated for white men are applicable to other races.

PATIENTS AND METHODS

Three-hundred and thirty-five healthy Japanese men, aged 40-79 years, residing in the small fishing village of Shimamaki-mura, Japan, agreed to enter this prospective, community-based study. All underwent a detailed clinical evaluation that included a serum PSA determination, a digital rectal examination and a transrectal ultrasound. Two-hundred and eighty-six (85%) completed the prostatic evaluation and had no evidence of prostate cancer by any one of the three diagnostic tests; these men formed the study population on which all analyses were performed.

RESULTS

The serum PSA concentration correlated directly with patient age (r = 0.33; P < 0.001) and prostatic volume (r = 0.57; P < 0.001). PSA density (PSAD) also was directly proportional to age (r = 0.30; P < 0.001). Adjusting for age, the serum PSA concentration was lower for Japanese men than for white men (P < 0.001). Thus, the recommended age-specific reference ranges (95th percentile) for serum PSA for Japanese were lower as well: 0.0-2.0 ng/mL for 40-49 years; 0.0-3.0 ng/mL for 50-59 years; 0.0-4.0 ng/mL for 60-69 years; and 0.0-5.0 ng/mL for 70-79 years. Based on transrectal ultrasound-volume determinations, the lower serum PSA concentrations in Japanese men are due in large part to their smaller prostate glands as compared with white men (P < 0.001).

CONCLUSIONS

These findings confirm the earlier observations that serum PSA, prostatic volume and PSAD are age-dependent. However, because of physiological differences among the two races, partly due to the size of the prostate gland, the age-specific reference ranges for serum PSA are lower for Japanese men than for white men. Because of these racial differences, it is now crucial to conduct a similar investigation among black men.