2295 DOES HEMODILUTION OR DECREASED CIRCULATING ANDROGENS EXPLAIN LOWER PSA CONCENTRATIONS AMONG OBESE MEN? - RESULTS FROM THE REDUCE TRIAL

Abstract

You have accessJournal of UrologyProstate Cancer: Markers1 Apr 20112295 DOES HEMODILUTION OR DECREASED CIRCULATING ANDROGENS EXPLAIN LOWER PSA CONCENTRATIONS AMONG OBESE MEN? - RESULTS FROM THE REDUCE TRIAL Lionel L. Bañez, Leah Gerber, Daniel M. Moreira, Madeline G. McKeever, Roger Rittmaster, Gerald L. Andriole, and Stephen J. Freedland Lionel L. BañezLionel L. Bañez Durham, NC More articles by this author , Leah GerberLeah Gerber Durham, NC More articles by this author , Daniel M. MoreiraDaniel M. Moreira Durham, NC More articles by this author , Madeline G. McKeeverMadeline G. McKeever Durham, NC More articles by this author , Roger RittmasterRoger Rittmaster Research Triangle Park, NC More articles by this author , Gerald L. AndrioleGerald L. Andriole St. Louis, MO More articles by this author , and Stephen J. FreedlandStephen J. Freedland Durham, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2540AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Lower serum PSA levels in men with increased body mass index (BMI) can potentially be explained by two distinct hypotheses: 1) As obese men have greater plasma volume and PSA levels are expressed as amount of PSA protein per volume of plasma, lower PSA levels among obese men may result from plasma hemodilution. 2) Because PSA production is androgen-driven, increased aromatase activity can lead to increased estradiol levels resulting in decreased circulating androgens and subsequent lower PSA levels. We determined whether PSA concentrations were lower in obese men in the REDUCE chemoprevention trial and whether hemodilution or decreased serum androgens contributed to lower PSA results among these men. METHODS We analyzed data from 7,572 men from the REDUCE trial with available anthropometric information. All participants had a negative prostate biopsy within six months prior to enrollment. Height and weight measurements at baseline were used to calculate BMI and estimate plasma volume. Mean-adjusted baseline PSA values for each BMI category (<25, 25–29.9, 30–34.9, ≥35 kg/m2) were calculated and tested for trend. Associations between PSA values at trial enrollment and plasma volume, serum testosterone, serum dihydrotestosterone (DHT) and BMI were assessed using linear regression models controlling for age, race, family history of CaP and prostate volume. RESULTS Median BMI was 26.9 kg/m2. Over 20% of the men were obese (n=1,547). Mean-adjusted PSA significantly decreased across increasing BMI categories (see table 1). After adjusting for demographic and clinical covariates, plasma volume was found to be inversely associated with PSA levels [β= −0.19; 95% CI (−0.31, −0.08); p=0.001]. Serum testosterone (p=0.89) and serum DHT levels (p=0.12) were not associated with PSA levels. When androgens but not plasma volume were controlled for, BMI was inversely associated with PSA [β= −0.09; 95% CI (−0.15, −0.03); p=0.002]. However, adding plasma volume to the model completely attenuated the association and BMI was no longer associated with PSA (p=0.53). Table 1. Mean-adjusted PSA (95% CI) by BMI Category⁎ less than 25 kg/m2 25-29.9 kg/m2 30-34.9 kg/m2 ≥35 kg/m2 p-trend PSA (ng/ml) 5.70 (5.62,5.79) 5.55 (5.49,5.61) 5.54 (5.44,5.65) 5.41 (5.20,5.62) 0.004 ⁎ adjusted for age, race, family history of prostate cancer, prostate volume, serum testosterone and serum DHT CONCLUSIONS In a large randomized CaP chemoprevention trial, obese men had lower PSA levels which appeared to be explained by hemodilution rather than decreased circulating androgen levels. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e920 Peer Review Report Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Lionel L. Bañez Durham, NC More articles by this author Leah Gerber Durham, NC More articles by this author Daniel M. Moreira Durham, NC More articles by this author Madeline G. McKeever Durham, NC More articles by this author Roger Rittmaster Research Triangle Park, NC More articles by this author Gerald L. Andriole St. Louis, MO More articles by this author Stephen J. Freedland Durham, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...