Significant predictors were ( log base 2 ) PSA ( odds ratio for low-grade vs no cancer , 1.29 * ; high-grade vs no cancer , 2.02 * ; high-grade vs low-grade cancer , 1.57 * ) , digital rectal examination ( 0.96 , 1.49 * , 1.55 * , respectively ) , age ( 1.02 * , 1.05 * , 1.03 * , respectively ) , African American race ( 1.13 , 2.83 * , 2.51 * , respectively ) , prior biopsy ( 0.63 * , 0.81 , 1.27 , respectively ) , and family history ( 1.31 * , 1.25 , 0.95 , respectively ) , where * indicates P value < .05 .