Significant predictors were ( log base @ ) PSA ( odds ratio for low-grade vs no cancer , @ * ; high-grade vs no cancer , @ * ; high-grade vs low-grade cancer , @ * ) , digital rectal examination ( @ , @ * , @ * , respectively ) , age ( @ * , @ * , @ * , respectively ) , African American race ( @ , @ * , @ * , respectively ) , prior biopsy ( @ * , @ , @ , respectively ) , and family history ( @ * , @ , @ , respectively ) , where * indicates P value < @ .