Relationship Between Prostate-specific Antigen, Age, and Body Mass Index in a Prostate Cancer Screening Population

Background: Recent studies questioning the benefit of prostate-specific antigen (PSA) screening have increased the need for evaluating factors contributing to variance in levels and their clinical relevance. An inverse relationship between body mass index (BMI) and PSA has been illustrated, however the clinical implications have not been specified. We performed a retrospective review of patients screened through our free screening clinic to delineate any relationship between PSA and BMI in an attempt to understand its possible clinical significance. Methods: The authors retrospectively reviewed data collected in relation to PSA values and patient characteristics from a community outreach program supplying information and screening for prostate cancer between June of 2003 and August of 2009. Results: Mean BMI of our patient population was 28.7 m/kg(2) (SD 5.4) and our mean PSA value was 1.28 (SD 1.77). Our data indicate a small, but statistically significant decrease in PSA for an increasing BMI with a 0.026 decrease in PSA for every unit increase in BMI. Conclusions: Our study confirms the previously reported inverse relationship between PSA value and BMI. The significance of this finding and its impact on the value do not seem to indicate a rationale to change the accepted abnormal value in obese patients and should be used in the context of the clinical scenario and other PSA altering factors.