Table 2.

Trichomonas vaginalis antibody distribution¹ for 616 prostate cancer cases and 616 frequency-matched controls in the Prostate Cancer Prevention Trial

	Case2	Control	P-value3
OD (mean)	0.39	0.40	0.32
P/N4 (mean)	2.28	2.33	0.40
Score5 (%):
0	63.3	60.2
1	21.5	24.8
2	13.1	13.8	0.33
3	2.1	1.2
4	0.0	0.0
5	0.0	0.0
≥2	15.2	15.0	0.396

OD=optical density, P/N=positive to negative ratio

¹Standardized by age, treatment arm, family history of prostate cancer and race (non-white versus white) using linear regression.

²Cases were a sample of men diagnosed with prostate cancer on any biopsy after their second visit or on their end-of-study biopsy (1996–2003).

³P-values were calculated by linear regression for continuous variables, and by generalized logit models for categorical variables.

⁴P/N values were calculated by dividing the average duplicate OD value for each specimen by the average duplicate OD value for the seronegative control included in each run.

⁵Scores were derived by comparing the P/N for each specimen to the P/N for the five seropositive controls with increasing positivity (1–5) included in each run.

⁶P-value for the comparison of 0, 1, and ≥2 scores.