Serum testosterone levels in African-American and white men undergoing prostate biopsy

Because androgen levels are known to influence prostate growth, we performed a prospective analysis of serum testosterone levels in all African-American and white men who underwent transrectal ultrasound-guided prostate biopsies to evaluate an abnormal digital rectal examination (DRE) and/or serum prostate-specific antigen (PSA) level greater than 4 ng/mL.

From June 1996 through July 1998, we evaluated 453 men (189 African-American and 264 white men) who underwent prostate needle biopsy because of an abnormal DRE or serum PSA greater than 4 ng/mL, or both. All men had morning serum testosterone levels determined just before undergoing prostate needle biopsy. Serum testosterone levels were compared on the basis of the prostate biopsy result (positive or negative for prostate cancer) and by race.

A total of 453 men underwent prostate biopsy and had morning serum testosterone levels available for comparison. Of the 264 white men who underwent biopsy, 88 (33%) were found to have prostate cancer compared with 67 (35%) of 189 African-American men who underwent biopsy. In the white men without cancer, the mean serum testosterone level was 380. 19 ng/dL; those with prostate cancer had a mean serum testosterone level of 419.52 ng/dL. The mean serum testosterone level in African-American men without cancer was 424.30 ng/dL; it was 386.55 ng/dL in those with prostate cancer. There was no statistical difference in serum testosterone levels based on biopsy result or race.

Although several studies have suggested that African-American men have higher serum testosterone levels than white men, these differences were noted only in men 40 years of age or younger. As was noted in our study, after age 40, African-American and white men have comparable serum testosterone levels. In addition, although prostate growth is androgen dependent, we found no difference in serum testosterone levels in men with and without prostate cancer.