1. ¹Vanderbilt Epidemiology Center, Vanderbilt University Medical Center, Nashville, TN, USA
2. ²Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
3. ³International Epidemiology Institute, Rockville, MD, USA
4. ⁴Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA

Correspondence: Dr JH Fowke, Institute for Medicine and Public Health, Vanderbilt University Medical Center, 6th floor, Suite 600, 2525 West End Avenue, Nashville, TN 37203-1738, USA. E-mail: jay.fowke@vanderbilt.edu

Received 27 August 2007; Revised 21 September 2007; Accepted 21 September 2007; Published online 16 October 2007.

Abstract

Prior studies report slightly lower prostate-specific antigen (PSA) levels among obese men. To understand this effect, we investigated the association between PSA and blood HbA1c, C-peptide, leptin and adiponectin levels in African-American (AA) (n=121) and Caucasian (CA) (n=121) men. Among AA men, PSA levels decreased with increasing C-peptide levels (PSA=0.99, 0.93, 0.75 and 0.53 ng ml^-1 across quartiles of C-peptide, respectively; P_trend=0.005). Among CA men, PSA levels decreased with increasing HbA1c (PSA=0.84, 0.73, 0.77 and 0.45 ng ml^-1 across quartiles of HbA1c, respectively; P_trend=0.005). This may suggest that metabolic disturbances related to metabolic syndrome or diabetes affect the ability to detect early-stage prostate cancer.