Weight a factor in PSA testing

Obese men have lower levels of a protein used to screen for prostate cancer risk, researchers have found, suggesting that doctors should take weight into account when determining a man’s risk.

The finding may help explain why overweight men are likely to be diagnosed when their disease is more advanced, the researchers wrote in the Oct. 9 issue of the journal Cancer.

The test is for prostate specific antigen, or PSA. This protein is produced only by prostate cells and circulates in the blood. Levels rise when a prostate is growing -- which could indicate cancer, or a condition called benign prostatic hypertrophy.

Researchers tested blood from 150 black men and 149 white men. They found that the more overweight the men were, the lower their PSA levels. Race appeared to have no effect.