Table 1.
Baseline characteristics1 of participants by prostate cancer status and T. vaginalis antibody score in the Prostate Cancer Prevention Trial
| Case-control status | T. vaginalis antibody score2 (controls only) | ||||||
|---|---|---|---|---|---|---|---|
| Case (n=616) | Control (n=616) | P-value3 | 0 (n=368) | 1 (n=154) | ≥2 (n=94) | P-value3 | |
| Mean age (years) | 64.0 | 64.0 | Matched | 63.7 | 64.0 | 64.7 | 0.31 |
| Finasteride (%) | 48.9 | 48.9 | Matched | 48.6 | 47.4 | 52.1 | 0.76 |
| First-degree relative with prostate cancer (%) | 20.6 | 20.6 | Matched | 21.7 | 22.1 | 13.8 | 0.21 |
| Race (%): | |||||||
| White | 90.4 | 78.9 | 80.4 | 79.2 | 72.3 | ||
| Black | 6.2 | 10.2 | N/A4 | 10.3 | 9.1 | 11.7 | 0.16 |
| Other race/ethnicity | 3.4 | 10.9 | 9.2 | 11.7 | 16.0 | ||
| Education (%): | |||||||
| Some high school or less | 5.3 | 4.3 | 4.6 | 4.6 | 4.3 | ||
| High school graduate | 14.8 | 14.9 | 0.72 | 12.8 | 19.5 | 17.0 | 0.29 |
| Some post-secondary education or more | 79.9 | 80.8 | 82.6 | 76.0 | 78.7 | ||
| Occupation (%): | |||||||
| Professional | 65.4 | 63.8 | 61.1 | 65.6 | 68.1 | ||
| Craftsman | 12.9 | 12.9 | 15.2 | 9.7 | 11.7 | ||
| Sales | 9.5 | 8.8 | 0.73 | 10.6 | 5.2 | 6.4 | 0.15 |
| Farming | 1.5 | 2.3 | 1.4 | 4.6 | 2.1 | ||
| Other | 10.6 | 12.3 | 11.7 | 14.9 | 11.7 | ||
| Military experience (%)5 | 25.9 | 28.3 | 0.14 | 30.1 | 30.0 | 29.3 | 0.98 |
| Marital status (%): | |||||||
| Currently married or in marriage-like relationship | 88.9 | 90.3 | 89.7 | 92.9 | 86.2 | ||
| Divorced/widowed | 8.8 | 7.3 | 0.63 | 7.9 | 5.2 | 10.6 | 0.90 |
| Never married | 2.1 | 2.4 | 2.4 | 2.0 | 3.2 | ||
| Mean height (inches) | 69.9 | 69.7 | 0.39 | 69.7 | 69.8 | 69.6 | 0.80 |
| Mean body mass index (kg/m2) | 27.6 | 27.6 | 0.87 | 27.4 | 27.8 | 27.8 | 0.55 |
| Mean intakes of: | |||||||
| Energy (kcal/day) | 2171.3 | 2140.7 | 0.53 | 2148.8 | 2148.4 | 2005.2 | 0.32 |
| Protein (g/day) | 92.3 | 92.1 | 0.93 | 92.2 | 93.0 | 86.8 | 0.46 |
| Carbohydrate (g/day) | 264.7 | 259.4 | 0.37 | 257.8 | 265.6 | 244.7 | 0.30 |
| Fat (g/day) | 79.8 | 78.6 | 0.59 | 79.5 | 77.5 | 73.5 | 0.43 |
| Fruit consumption (fruit/day) | 2.2 | 2.0 | 0.03 | 2.0 | 2.1 | 2.0 | 0.58 |
| Vegetable consumption (vegetables/day) | 2.3 | 2.3 | 0.59 | 2.3 | 2.4 | 2.1 | 0.17 |
| Tomato products (1 cup servings/day) | 0.48 | 0.47 | 0.81 | 0.46 | 0.46 | 0.40 | 0.06 |
| Red meat (6 oz servings/day) | 0.60 | 0.63 | 0.27 | 0.62 | 0.67 | 0.57 | 0.18 |
| Processed meat (6 oz servings/day) | 0.35 | 0.38 | 0.23 | 0.36 | 0.43 | 0.36 | 0.07 |
| Fish (6 oz servings/day) | 0.23 | 0.21 | 0.19 | 0.20 | 0.23 | 0.20 | 0.42 |
| Calcium from food plus supplements (mg/day) | 1073 | 1063 | 0.76 | 1067 | 1050 | 991 | 0.49 |
| Zinc from food plus supplements (mg/day) | 25.5 | 25.4 | 0.93 | 26.0 | 23.7 | 25.1 | 0.52 |
| Total alcohol (g/day) | 9.3 | 8.9 | 0.64 | 9.5 | 7.5 | 7.7 | 0.25 |
| Cigarette smoking: | |||||||
| Smoked regularly before 25 years of age (%) | 61.7 | 63.8 | 0.44 | 62.0 | 68.2 | 66.0 | 0.37 |
| Currently smoke (%) | 6.1 | 6.6 | 0.70 | 7.9 | 4.6 | 7.4 | 0.39 |
| Mean pack-years smoked | 22.0 | 24.1 | 0.05 | 24.1 | 22.7 | 25.7 | 0.45 |
| Physical activity (%): | |||||||
| Sedentary | 14.7 | 15.8 | 19.6 | 9.9 | 11.1 | ||
| Light activity | 44.6 | 40.2 | 0.25 | 39.2 | 35.8 | 51.1 | 0.28 |
| Moderate activity | 33.2 | 32.0 | 29.6 | 39.5 | 28.9 | ||
| Very active | 7.5 | 12.0 | 11.6 | 14.8 | 8.9 | ||
| Frequency of sexual activity in the past 4 weeks (%): | |||||||
| Not at all | 14.0 | 12.0 | 11.7 | 10.4 | 14.9 | ||
| Once | 11.7 | 12.5 | 11.4 | 13.6 | 13.8 | ||
| 2–3 times | 23.4 | 24.3 | 0.46 | 22.8 | 28.6 | 22.3 | 0.84 |
| Once/week | 30.9 | 27.7 | 29.1 | 28.6 | 21.3 | ||
| 2–3 times/week | 16.7 | 19.5 | 20.1 | 16.2 | 23.4 | ||
| ≥4 times/week | 2.1 | 3.3 | 3.8 | 2.6 | 3.2 | ||
| Vasectomy (%) | 29.4 | 31.2 | 0.49 | 30.7 | 29.9 | 28.7 | 0.93 |
| Mean age at vasectomy | 38.7 | 37.5 | 0.11 | 37.4 | 38.0 | 38.6 | 0.71 |
| History of diabetes mellitus type 2 (%) | 6.2 | 7.1 | 0.54 | 9.2 | 3.2 | 8.5 | 0.06 |
| Aspirin use on a regular basis (%): | |||||||
| Current use | 42.5 | 40.8 | 0.53 | 36.1 | 46.8 | 43.6 | 0.06 |
| Past use | 8.1 | 8.6 | 0.76 | 7.9 | 8.4 | 13.8 | 0.19 |
Case and control values collected at baseline in 1994–7 or at the first annual visit were standardized by age, treatment arm, family history of prostate cancer and race (non-white versus white) using linear regression.
Scores were derived by first calculating the ratio of the average duplicate optical density value for each participant’s specimen to the average duplicate optical density value for the seronegative control included in each run, and then comparing this value to the corresponding values for the five seropositive controls with increasing positivity (1–5) also included in each run.
P-values were calculated by linear regression for continuous and binary variables, and by generalized logit models for categorical variables.
Black controls and controls of other race/ethnicity were over-sampled in the design of the study. All analyses are adjusted for race to take this feature of the design into account.
May underestimate the true prevalence of military experience in this population.