The effects of type 2 diabetes and hypertension on changes in serum prostate specific antigen levels: results from the Olmsted County study.

OBJECTIVE

Men with type 2 diabetes have lower concomitant prostate-specific antigen (PSA) levels; however, the influence of metabolic conditions on PSA changes over time remains unknown. Therefore, the goal of this study was to assess associations between type 2 diabetes and hypertension and changes in serum PSA levels.

METHODS

In 1990, a randomly selected cohort of Caucasian men, ages 40-79, from Olmsted County, MN completed questionnaires ascertaining demographic characteristics, current medical conditions and medications biennially, with 633 men undergoing blood draws. Men with a physician diagnosis of diabetes or hypertension at baseline, or who reported using medications to treat these conditions prior to baseline were considered exposed. Men with at least two serum PSA measurements (n = 569) were included in this analysis. Linear mixed models were used to estimate the annual percent change in serum PSA levels associated with diabetes and hypertension, adjusting for baseline age.

RESULTS

The overall mean change in serum PSA levels was 3.6% per year and increased with age (P = .009). Men with diabetes experienced less annual change in serum PSA levels (1.1%) than did non-diabetic men (3.7%), adjusting for age (P = .02). Age-adjusted change in serum PSA levels differed little by hypertension status (3.7% vs. 3.6%; P = .49).

CONCLUSIONS

Our results suggest that Caucasian men with type 2 diabetes experience smaller increases in serum PSA levels as they age compared to men without diabetes. Additional research is needed to elucidate whether this difference results in a relatively lower incidence of prostate cancer or less cancer detection among diabetic men.