New research indicates that PSA levels decrease as body weight goes up, a finding that could have important implications for prostate cancer screening.

Previous reports have shown that obese men with prostate cancer generally fare worse than leaner men. The new findings suggest that this may stem from a delay in diagnosis rather than from any intrinsic difference in prostate tumors.

Dr. Jacques Baillargeon, from the University of Texas Health Science Center in San Antonio, and colleagues assessed the link between body mass index (BMI) - a measure of weight in relation to height - and PSA levels in almost 2800 men without prostate cancer

As they report in the issue of the journal Cancer, the investigators found that the PSA level was inversely related to BMI.

Average PSA values ranged from 1.01 among normal weight men to 0.69 for men in the highest obesity category with a BMI of 40 or more. This trend held true after adjusting for age and race.

“Given the increased rates of obesity in the US,” the team says it’s “critically important” to understand how obesity affects screening for prostate cancer and the development of the disease.

“Future investigations,” they add, “should assess whether considerations of BMI in PSA interpretation results in earlier detection” - and, ultimately, in better prognosis for obese men.

SOURCE: Cancer, online January 24, 2005.