TABLE 1.
Dietary antioxidants and risk of Parkinson's disease1
| Highest vs. lowest category meta-analysis | Dose-response meta-analysis | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Studies, n | RR (95% CI) | I2, % (95% CI) | P-heterogeneity | Dose, unit | Studies, n | RR (95% CI) | I2, % | P-heterogeneity | |
| Cohort studies | |||||||||
| Vitamin C | 7 | 0.95 (0.77, 1.18) | 75.9 (49, 89) | <0.001 | 50 mg/d | 6 | 0.94 (0.88, 0.99) | 55.2 | 0.06 |
| Vitamin E | 7 | 0.84 (0.71, 0.99) | 51.9 (0, 80) | 0.05 | 5 mg/d | 7 | 0.84 (0.70, 0.99) | 58.3 | 0.02 |
| Vitamin A | 2 | 1.11 (0.92, 1.33) | 0.0 (0, 90) | 0.33 | 1000 IU/d | 1 | 1.00 (0.94, 1.06) | — | — |
| α-Carotene | 3 | 1.06 (0.89, 1.25) | 0.0 (0, 90) | 0.46 | 0.5 mg/d | 3 | 0.98 (0.92, 1.04) | 0.4 | 0.36 |
| β-Carotene | 6 | 0.88 (0.76, 1.03) | 45.2 (0, 78) | 0.10 | 2 mg/d | 6 | 0.94 (0.89, 0.99) | 58 | 0.03 |
| β-Cryptoxanthin | 3 | 1.03 (0.88, 1.22) | 0.0 (0, 90) | 0.87 | 100 μg/d | 3 | 1.01 (0.96, 1.06) | 0.0 | 0.47 |
| Total carotenoids | 3 | 0.98 (0.81, 1.19) | 32.1 (0, 93) | 0.22 | 5 mg/d | 3 | 0.99 (0.91, 1.08) | 48.9 | 0.14 |
| Lycopene | 3 | 1.04 (0.88, 1.24) | 15.9 (0, 91) | 0.30 | 2 mg/d | 3 | 1.01 (0.97, 1.04) | 0.0 | 0.44 |
| Lutein | 3 | 1.00 (0.82, 1.21) | 34.5 (0, 79) | 0.21 | 1 mg/d | 3 | 1.00 (0.94, 1.06) | 44.2 | 0.16 |
| Total flavonoids | 2 | 0.77 (0.46, 1.29) | 77.1 | 0.03 | 100 mg/d | 2 | 0.95 (0.86, 1.04) | 83.4 | 0.01 |
| Flavonols | 2 | 0.80 (0.63, 1.00) | 0.0 | 0.44 | — | — | — | — | — |
| Anthocyanins | 2 | 0.76 (0.61, 0.96) | 0.0 | 0.54 | — | — | — | — | — |
| Flavones | 2 | 0.86 (0.68, 1.07) | 0.0 | 0.95 | — | — | — | — | — |
| Flavanones | 2 | 0.88 (0.63, 1.24) | 52.8 | 0.14 | — | — | — | — | — |
| Flavan-3-ols | 2 | 0.89 (0.61, 1.30) | 61.2 | 0.10 | — | — | — | — | — |
| Polymers | 2 | 0.79 (0.48, 1.31) | 77.2 | 0.03 | — | — | — | — | — |
| TAC | 2 | 0.93 (0.78, 1.11) | 0.0 | 0.67 | 2000 TE/d | 2 | 0.98 (0.94, 1.02) | 0.0 | 0.47 |
| NEAC | 1 | 0.79 (0.60, 1.04) | — | — | 5 mg/d | 1 | 0.96 (0.90, 1.03) | — | — |
| Case-control studies | |||||||||
| Vitamin C | 5 | 0.92 (0.72, 1.18) | 0.0 (0, 79) | 0.41 | 50 mg/d | 1 | 0.99 (0.76, 1.29) | — | — |
| Vitamin E | 5 | 0.80 (0.57, 1.12) | 23.4 (0, 69) | 0.26 | 5 mg/d | 1 | 0.34 (0.16, 0.69) | — | — |
| Vitamin A | 1 | 1.15 (0.62, 2.11) | — | — | — | — | — | — | — |
| α-Carotene | 2 | 0.82 (0.38, 1.78) | 51 | 0.15 | 0.5 mg/d | 1 | 0.65 (0.41, 1.02) | — | — |
| β-Carotene | 5 | 0.92 (0.64, 1.33) | 47.8 (0, 81) | 0.10 | 2 mg/d | 1 | 0.70 (0.51, 0.94) | — | — |
| β-Cryptoxanthin | 2 | 1.22 (0.80, 1.85) | 0.0 | 0.71 | 100 μg/d | 1 | 1.05 (0.95, 1.17) | — | — |
| Total carotenoids | 1 | 1.17 (0.49, 2.81) | — | — | — | — | — | — | — |
| Lycopene | 2 | 1.13 (0.50, 2.54) | 66.6 | 0.08 | — | — | — | — | — |
| Lutein | 3 | 1.86 (1.20, 2.88) | 23.4 (0, 92) | 0.27 | — | — | — | — | — |
| Zinc | 2 | 0.64 (0.31, 1.31) | 68.8 | 0.07 | 1 mg/d | 1 | 0.65 (0.49, 0.86) | — | — |
| Selenium | 1 | 1.01 (0.60, 1.70) | — | — | — | — | — | — | — |
| Total xanthophylls | 1 | 3.16 (1.08, 9.30) | — | — | — | — | — | — | — |
1
NEAC, nonenzymatic antioxidant capacity; TAC, total antioxidant capacity; TE, Trolox equivalents.