Overweight and obese men carry lower concentrations of prostate-specific antigen (PSA) than average-weight men, a finding from an earlier study that researchers at Duke University Medical Center have confirmed in the wider population. Researchers sought to determine whether high, early-life body mass index (BMI) correlated with current BMI and the results of PSA tests and digital rectal examination for prostate abnormalities. They found that higher BMI did associate with lower PSA values—mildly and moderately-to-severely obese men had PSA scores 14% and 29% lower, respectively, than normal-weight men—but that weight had no significant association with digital exam findings. The researchers believe the greater blood volume of obese men dilutes their PSA levels, which—combined with evidence of greater posttreatment cancer progression and mortality in obese men—may lead doctors to miss positive cancer diagnoses and delay treatment. They conclude that the PSA threshold for a positive result should be adjusted for the patient's obesity level, and that all patients should pursue healthy lifestyles and be screened regularly to cut their odds of developing advanced prostate cancer.

http://Eurekalert.org/. "Overweight and obese men have lower PSA values, even before they get prostate cancer." 2008. http://www.eurekalert.org/pub_releases/2008-02/dumc-oao021908.php (11 Mar. 2008).

Price, M. M., Hamilton, R. J., et al. "Body mass index, prostate-specific antigen, and digital rectal examination findings among participants in a prostate cancer screening clinic." 2008. http://www.goldjournal.net/article/S0090-4295(07)02407-7/fulltext/ (11 Mar. 2008).