Plasma volume changes affect prostate specific antigen in healthy men.

Area of Science:

• Urology
• Biochemistry
• Clinical Chemistry

Background:

• Prostate specific antigen (PSA) levels are inversely correlated with body mass index (BMI).
• Obesity-related hemodilution is a proposed mechanism for lower PSA in obese men.
• Hematocrit serves as a key indicator of plasma volume fluctuations.

Purpose of the Study:

• To investigate the effect of hematocrit changes on prostate specific antigen (PSA) levels in healthy men over two years.
• To explore the association between PSA and plasma volume changes, considering combined shifts in body weight and hematocrit.

Main Methods:

• Analysis of health assessment records from 8,338 men between 2005 and 2007.
• Definition of hemodilution (weight gain with decreased hematocrit) and hemoconcentration (weight loss with increased hematocrit) based on annual changes.
• Multiple regression analysis controlling for age and weight change.

Main Results:

• Hematocrit change showed a significant positive association with PSA change (p <0.001).
• Men experiencing hemoconcentration exhibited significantly greater PSA changes (6.1% and 4.8%) compared to those with hemodilution (p <0.001).
• These associations remained significant after controlling for age and weight changes.

Conclusions:

• Hematocrit fluctuations are positively associated with changes in prostate specific antigen levels.
• Hemoconcentration, compared to hemodilution, is linked to more substantial PSA level alterations.
• Plasma volume variations, reflected by hematocrit, likely explain the inverse relationship observed between BMI and PSA.