The inverse relationship between prostate specific antigen (PSA) and obesity
Adel T Aref1,2, Andrew D Vincent1,2, Michael E O'Callaghan1,3,4,5
1University of Adelaide Medical School and Freemasons Foundation Centre for Men's HealthAdelaide, South Australia, Australia.
Endocrine-Related Cancer
|June 27, 2018
Summary
Obese men have lower prostate-specific antigen (PSA) due to hormonal changes and hemodilution. Elevated estradiol/testosterone ratio significantly explains reduced PSA in obesity, highlighting hormonal factors in this association.
Area of Science:
- Endocrinology
- Urology
- Men's Health
Background:
- Obesity is linked to lower serum prostate-specific antigen (PSA) levels in men.
- The precise mechanisms underlying this association remain incompletely understood.
- Understanding these mechanisms is crucial for accurate PSA interpretation in obese individuals.
Purpose of the Study:
- To investigate the effect of obesity on PSA levels.
- To explore potential mediating mechanisms, including hormonal and volumetric factors.
- To elucidate the relationship between obesity, hormones, and PSA.
Main Methods:
- Analysis of a cohort of 970 men aged 35+ with anthropometric, hormonal, and PSA data.
- Utilized mixed-effects regressions and mediation analyses.
- Adjusted for age, body mass index (BMI), waist circumference (WC), estradiol (E2)/testosterone ratio, and plasma volume (PlasV).
Main Results:
- Higher waist circumference (WC) was associated with lower PSA after age adjustment.
- In multivariable models, WC and plasma volume (PlasV) were not significantly associated with PSA.
- The estradiol (E2)/testosterone ratio significantly predicted lower PSA (P < 0.001).
- Mediation analysis indicated hormonal changes explained ~50% of the effect of WC on PSA (P < 0.001).
Conclusions:
- Lower PSA levels in obese men are significantly explained by hormonal alterations, specifically an elevated E2/testosterone ratio.
- Hemodilution also contributes to lower PSA in obese men.
- Hormonal factors represent a substantial, underappreciated pathway linking obesity to reduced PSA levels.
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