Table 1.
Population baseline characteristics by quintile of serum α-tocopherol concentration
| Quintile of baseline serum α-tocopherol | |||||
|---|---|---|---|---|---|
| Characteristics | Q1 ≤ 9.3 mg/L (n=5 806) | Q2 > 9.3 and ≤ 10.8 mg/L (n=5 882) | Q3 > 10.8 and ≤ 12.2 mg/L (n=5 653) | Q4 > 12.2 and ≤ 14.2 mg/L (n=5 938) | Q5 > 14.2 mg/L (n=5 823) |
| Age at randomization, y | 57 (53–62) | 57 (53–61) | 56 (53–61) | 56 (53–61) | 56 (53–60) |
| Weight, kg | 75.7 (67.3–84.8) | 77.2 (69.2–85.7) | 78.3 (70.9–86.9) | 78.7 (71.4–87.3) | 80.9 (73.7–89.4) |
| Height, cm | 173 (169–177) | 173 (169–178) | 174 (170-1-78) | 174 (169–178) | 174 (170–178) |
| BMI, kg/m2 | 25.2 (22.7–28.0) | 25.6 (23.3–28.2) | 25.9 (23.7–28.4) | 26.2 (24.0–28.6) | 26.8 (24.7–29.3) |
| History of diabetes (%) | |||||
| Yes | 4.1 | 3.4 | 3.7 | 3.6 | 6.4 |
| No | 95.9 | 96.6 | 96.3 | 96.4 | 93.6 |
| Cigarettes per day | 20 (15–25) | 20 (15–25) | 20 (15–25) | 20 (15–25) | 20 (15–25) |
| Years of cigarette smoking | 38 (32–43) | 37 (31–42) | 36 (30–41) | 36 (30–41) | 36 (30–41) |
| Education (%) | |||||
| Less than high school | 40.2 | 37.5 | 33.7 | 31.5 | 27.3 |
| High school graduate and above | 59.8 | 62.5 | 66.3 | 68.5 | 72.7 |
| Physical exercise in leisure time (%) | |||||
| < 1 per week | 54.9 | 53.8 | 51.1 | 48.5 | 49.5 |
| 1–2 per week | 25.4 | 26.8 | 29.1 | 30.9 | 30.3 |
| ≥3 or more per week | 19.6 | 19.2 | 19.6 | 20.5 | 20.1 |
| Family history of prostate cancer n (%)a | |||||
| Yes | 1.8 | 2.2 | 2.4 | 2.3 | 2.0 |
| No | 56.2 | 62.2 | 63.4 | 65.3 | 65.2 |
| Baseline serum β-carotene, μg/L | 123 (77–189) | 164 (110–242) | 182 (122–270.5) | 195 (130–293) | 196 (127–309) |
| Baseline serum retinol, μg/L | 538.3 (464–624) | 560 (489–639) | 575 (503–654) | 590 (515–673) | 619 (542–710) |
| Baseline serum total cholesterol, mmol/L | 5.2 (4.7–5.8) | 5.8 (5.3–6.3) | 6.2 (5.6–6.8) | 6.6 (6.0–7.2) | 7.2 (6.5–7.9) |
| Dietary intake | |||||
| Total energy, kcal | 2 617 (2161–3159) | 2 629 (2165–3148) | 2 628 (2188–3131) | 2 588 (2153–3106) | 2 538 (2117–3060) |
| Fruits, g | 61 (26–112) | 68 (30–120) | 77 (34–127) | 80.5 (38.3–132.4) | 84.2 (40–138) |
| Vegetables. g | 57 (34–91) | 65 (40–101) | 71 (44–109) | 76 (47–116) | 82 (51–123) |
| Red meat, g | 64 (47–85) | 65 (48–88) | 66 (50–88) | 66 (48–88) | 66 (49–88) |
| Coffee, g | 550 (330–770) | 560 (420–770) | 600 (440–770) | 560 (440–770) | 550 (420–770) |
| Alcohol, g ethanol | 12.9 (3.2–29.3) | 10.9 (2.3–25.9) | 10.7 (2.5–25.0) | 10.3 (2.4–24.0) | 10.7 (2.7–24.4) |
| Vitamin A, μg | 1 556.4 (1071–2251) | 1 619 (1116–2365) | 1 639 (1129–2413) | 1 641 (1110–2418) | 1 631 (1100–2354) |
| Vitamin C, mg | 85 (60–114) | 90 (65–119) | 94 (70–125) | 96 (70–128) | 98 (73–131) |
| Vitamin E, mg | 9.2 (7.1–12.0) | 10.1 (7.8–13.3) | 10.9 (8.3–14.3) | 11.4 (8.6–15.7) | 12.4 (9.3–17.0) |
| α-Tocopherol, mg | 7.9 (6.2–10.3) | 8.7 (6.7–11.5) | 9.3 (7.2–12.2) | 9.8 (7.4–13.4) | 10.7 (8.0–14.7) |
| γ-Tocopherol, mg | 3.9 (2.1–7.2) | 5.0 (2.7–9.2) | 5.9 (3.1–10.8) | 6.8 (3.5–12.8) | 8.3 (4.3–14.9) |
| Trial intervention group | |||||
| α-tocopherol only, n (%) | 1501 (25.9) | 1473 (25.0) | 1369 (24.2) | 1473 (24.8) | 1463 (25.1) |
| β-carotene only, n (%) | 1461 (25.2) | 1485 (25.3) | 1384 (24.5) | 1459 (24.6) | 1489 (25.6) |
| α-tocopherol and β-carotene, n (%) | 1404 (24.2) | 1438 (24.5) | 1426 (25.2) | 1530 (25.8) | 1470 (25.2) |
| Placebo, n (%) | 1440 (24.8) | 1486 (25.3) | 1474 (26.1) | 1476 (24.9) | 1401 (24.1) |
Note: Median (interquartile range) unless otherwise indicated.
a
Family history of prostate cancer was not captured at baseline but on-study
Abbreviations: Q, quintile; BMI, Body mass index;