Obesity-related plasma hemodilution & PSA concentration among menw/pc

Obesity-related plasma hemodilution and PSA concentration among men with
prostate cancer.

Bañez LL, Hamilton RJ, Partin AW, Vollmer RT, Sun L, Rodriguez C,
Wang Y, Terris MK, Aronson WJ, Presti JC Jr, Kane CJ, Amling CL, Moul
JW, Freedland SJ.

Division of Urologic Surgery and the Duke Prostate Center, and
Department of Surgery, Duke University Medical Center, Durham, NC 27710,
USA.

CONTEXT: Recent studies have suggested that obese men have lower serum
prostate-specific antigen (PSA) concentrations than nonobese men.
Because men with higher body mass index (BMI) have greater circulating
plasma volumes, lower PSA concentrations among obese men may be due to
hemodilution.

OBJECTIVE: To determine the association between hemodilution and PSA
concentration in obese men with prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of men who
underwent radical prostatectomy for prostate adenocarcinoma from 1988 to
2006, using data from the databases of the Shared Equal Access Regional
Cancer Hospital (n = 1373), Duke Prostate Center (n = 1974), and Johns
Hopkins Hospital (n = 10 287). Multivariate linear regression models
adjusting for clinicopathological characteristics were used to analyze
the main outcome measures.

MAIN OUTCOME MEASURES: Associations between BMI and mean adjusted PSA
concentrations, mean plasma volume, and mean adjusted PSA mass (total
circulating PSA protein, calculated as PSA concentration multiplied by
plasma volume), assessed by determining P values for trend.

RESULTS: After controlling for clinicopathological characteristics,
higher BMI was significantly associated with higher plasma volume (P <
001 for trend) and lower PSA concentrations (P < or = .02 for trend) in
all cohorts. In 2 of the 3 cohorts, PSA mass did not change
significantly with increasing BMI. In the third cohort, higher BMI was
associated with increased PSA mass (P < .001 for trend), but only
between BMI category less than 25 and the other categories.

CONCLUSIONS: In men undergoing radical prostatectomy, higher BMI was
associated with higher plasma volume; hemodilution may therefore be
responsible for the lower serum PSA concentrations among obese men with
prostate cancer. Prospective studies are needed to evaluate this
association in screened populations.

PMID: 18029831 [PubMed - indexed for MEDLINE]

knowledge is power - growing old is mandatory - growing wise is optional
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
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