Table 2.
Antioxidant | No. of studies | RR | 95 % CI | I 2 (%) | 95 % CI | P heterogeneity | Meta-evidence | NutriGrade score | Explanation of the results according to recommendations of the NutriGrade scoring system |
---|---|---|---|---|---|---|---|---|---|
Dietary vitamin C | 10 | 0·79 | 0·68, 0·89 | 46 | 0, 74 | 0·06 | High | 8·4 | There is high confidence in the effect estimate, and further research probably will not change the confidence in the effect estimate |
Circulating vitamin C | 6 | 0·60 | 0·42, 0·78 | 65 | 15, 85 | 0·01 | Moderate | 6·4 | There is moderate confidence in the effect estimate; further research could add evidence on the confidence and may change the effect estimate |
Dietary vitamin E | 8 | 0·91 | 0·79, 1·03 | 51 | 0, 81 | 0·04 | Low | 5·4 | There is low confidence in the effect estimate; further research will provide important evidence on the confidence and likely change the effect estimate |
Circulating α-tocopherol | 5 | 0·82 | 0·76, 0·88 | 0 | 0, 79 | 0·55 | Low | 4·0 | There is low confidence in the effect estimate; further research will provide important evidence on the confidence and likely change the effect estimate |
Dietary β-carotene | 4 | 0·89 | 0·73, 1·05 | 35 | 0, 77 | 0·21 | Low | 5·5 | There is low confidence in the effect estimate; further research will provide important evidence on the confidence and likely change the effect estimate |
Circulating β-carotene | 6 | 0·68 | 0·52, 0·83 | 50 | 0, 80 | 0·07 | Low | 5·9 | There is low confidence in the effect estimate; further research will provide important evidence on the confidence and likely change the effect estimate |
RR, relative risk.