TABLE 1.

Characteristics of analytic sample at baseline (488 Matched Pairs)

Variable	Response	Cases	Controls	P value
Race*	white	290	290	–
	African American	198	198
Mean Age at cohort entry, y*		65.3 ± 7.4	65.4 ± 7.4	–
Date of 1st benign specimen*
Median		5/4/1995	4/12/1995	–
Range		1/19/90–11/25/02	1/18/90–9/30/02
Years to case diagnosis or follow-up time for controls*
Median		4.15	4.15	–
Range		1.01–15.09	1.01–15.09
Mean serum PSA at cohort entry, ng/mL		7.82 ± 7.40	5.91 ± 5.49	< 0.0001
Mean PSA velocity, ng/mL/year		7.97 ± 97.12	−0.06 ± 2.49	< 0.0001
Mean number of PSA tests from cohort entry to diagnosis (cases) or reference (controls) date		6.61 ± 3.56	5.55 ± 3.18	< 0.0001

Abbreviation: PSA, prostate-specific antigen.

^**Paired Wilcoxon Sign Rank Test

^*Matching variable.