TABLE 4.
Odds ratios (ORs) of prostate cancer according to quartiles (Q) of serum selenium stratified by low and high intake of antioxidative vitamin and carotenoids and by multivitamin use1
| Serum selenium
|
||||||
|---|---|---|---|---|---|---|
| Q1 (50.5 to < 126.8 ng/mL) | Q2 (≥ 126.8 to < 141.9 ng/mL) | Q3 (≥ 141.9 to < 158.0 ng/mL) | Q4 (≥ 158.0 to 253.0 ng/mL) | P for trend2 | P for interaction | |
| Vitamin C3 | 0.79 | |||||
| Low | ||||||
| Cases/controls (n) | 97/120 | 101/110 | 91/107 | 68/94 | ||
| OR4 | 1.00 | 1.02 | 1.18 | 0.96 | 0.705 | |
| 95% CI | — | 0.68, 1.55 | 0.77, 1.82 | 0.61, 1.51 | ||
| High | ||||||
| Cases/controls (n) | 89/94 | 85/105 | 101/111 | 68/121 | ||
| OR4 | 1.00 | 0.87 | 1.10 | 0.71 | 0.705 | |
| 95% CI | — | 0.56, 1.36 | 0.71, 1.71 | 0.45, 1.13 | ||
| Vitamin E3 | 0.01 | |||||
| Low | ||||||
| Cases/controls (n) | 86/125 | 96/115 | 91/102 | 64/89 | ||
| OR4 | 1.00 | 1.26 | 1.44 | 1.34 | 0.14 | |
| 95% CI | — | 0.83, 1.94 | 0.93, 2.25 | 0.84, 2.14 | ||
| High | ||||||
| Cases/controls (n) | 100/89 | 90/100 | 101/116 | 72/126 | ||
| OR4 | 1.00 | 0.80 | 0.84 | 0.58 | 0.05 | |
| 95% CI | — | 0.51, 1.24 | 0.55, 1.30 | 0.37, 0.91 | ||
| β-Carotene3 | 0.86 | |||||
| Low | ||||||
| Cases/controls (n) | 93/111 | 87/106 | 94/114 | 62/100 | ||
| OR4 | 1.00 | 0.99 | 1.21 | 0.89 | 0.705 | |
| 95% CI | — | 0.64, 1.53 | 0.79, 1.87 | 0.56, 1.41 | ||
| High | ||||||
| Cases/controls (n) | 93/103 | 99/109 | 98/104 | 74/115 | ||
| OR4 | 1.00 | 1.00 | 1.04 | 0.85 | 0.705 | |
| 95% CI | — | 0.66, 1.52 | 0.68, 1.58 | 0.54, 1.32 | ||
| Lycopene3 | 0.72 | |||||
| Low | ||||||
| Cases/controls (n) | 95/110 | 100/95 | 86/110 | 73/117 | ||
| OR4 | 1.00 | 1.30 | 1.12 | 0.95 | 0.705 | |
| 95% CI | — | 0.85, 2.00 | 0.72, 1.73 | 0.61, 1.49 | ||
| High | ||||||
| Cases/controls (n) | 91/104 | 86/120 | 106/108 | 63/98 | ||
| OR4 | 1.00 | 0.81 | 1.26 | 0.84 | 0.705 | |
| 95% CI | — | 0.53, 1.24 | 0.80, 1.89 | 0.53, 1.34 | ||
| Multivitamin use | 0.05 | |||||
| No | ||||||
| Cases/controls (n) | 109/143 | 110/134 | 101/121 | 78/120 | ||
| OR4 | 1.00 | 1.12 | 1.29 | 1.13 | 0.16 | |
| 95% CI | — | 0.76, 1.65 | 0.87, 1.93 | 0.74, 1.71 | ||
| Yes | ||||||
| Cases/controls (n) | 77/71 | 76/81 | 91/97 | 58/95 | ||
| OR4 | 1.00 | 0.89 | 1.00 | 0.61 | 0.06 | |
| 95% CI | — | 0.54, 1.49 | 0.61, 1.63 | 0.36, 1.04 | ||
Twenty-four cases and 17 controls without data on dietary and supplemental intake were excluded from all analyses in this table. Quartile 1 was the reference category.
Conducted by using serum selenium as a continuous variable.
Low and high are defined as below or above the median, respectively. The median for vitamin C was 241.7 mg/d, that for vitamin E was 28.0 IU/d, that for β-carotene was 4817.8 μg/d, and that for lycopene was 9693.6 μg/d. Vitamin C, vitamin E, and β-carotene are based on dietary and supplemental intakes, and lycopene is based on dietary intake from a 137-item food-frequency questionnaire that included 14 additional questions on intakes of vitamin and mineral supplements (43).
Obtained from a multivariate conditional logistic regression analysis adjusted for age, time since initial screening, year of blood draw, and study center.
For stratified analyses with no significant interaction, the P for trend for the combined analysis per Table 3 (P for trend = 0.70) was provided.