Department of Biological Chemistry and Nutritional Science, University of Hohenheim, Garbenstrasse 28, D-70593 Stuttgart, Germany.
Nutrients. 2010 Sep;2(9):929-49. doi: 10.3390/nu2090929. Epub 2010 Aug 30.
A recent meta-analysis of selected randomized clinical trials (RCTs), in which population groups of differing ages and health status were supplemented with various doses of β-carotene, vitamin A, and/or vitamin E, found that these interventions increased all-cause mortality. However, this meta-analysis did not consider the rationale of the constituent RCTs for antioxidant supplementation, none of which included mortality as a primary outcome. As the rationale for these trials was to test the hypothesis of a potential benefit of antioxidant supplementation, an alternative approach to a systematic evaluation of these RCTs would be to evaluate this outcome relative to the putative risk of greater total mortality. Thus, we examined these data based on the primary outcome of the 66 RCTs included in the meta-analysis via a decision analysis to identify whether the results provided a positive (i.e., benefit), null or negative (i.e., harm) outcome. Our evaluation indicated that of these RCTs, 24 had a positive outcome, 39 had a null outcome, and 3 had a negative outcome. We further categorized these interventions as primary (risk reduction in healthy populations) or secondary (slowing pathogenesis or preventing recurrent events and/or cause-specific mortality) prevention or therapeutic (treatment to improve quality of life, limit complications, and/or provide rehabilitation) studies, and determined positive outcomes in 8 of 20 primary prevention studies, 10 of 34 secondary prevention studies, and 6 out of 16 therapeutic studies. Seven of the eight RCTs with a positive outcome in primary prevention included participants in a population where malnutrition is frequently described. These results suggest that analyses of potential risks from antioxidant supplementation should be placed in the context of a benefit/risk ratio.
最近一项针对特定随机临床试验（RCT）的荟萃分析发现，对不同年龄和健康状况的人群群体补充不同剂量的β-胡萝卜素、维生素 A 和/或维生素 E，会增加全因死亡率。然而，该荟萃分析没有考虑组成 RCT 的补充抗氧化剂的基本原理，这些 RCT 都没有将死亡率作为主要结果。由于这些试验的基本原理是检验抗氧化剂补充潜在益处的假设，因此对这些 RCT 进行系统评估的替代方法是，相对于更大的全因死亡率的潜在风险来评估这种结果。因此，我们通过决策分析，根据荟萃分析中包含的 66 项 RCT 的主要结果来检查这些数据，以确定结果是否提供了阳性（即有益）、阴性（即有害）或中性（即无明显益处）的结果。我们的评估表明，在这些 RCT 中，有 24 项具有阳性结果，39 项具有中性结果，3 项具有阴性结果。我们进一步将这些干预措施分为主要（降低健康人群的风险）或次要（减缓发病或预防复发事件和/或特定原因的死亡率）预防或治疗（改善生活质量、限制并发症和/或提供康复的治疗）研究，并确定了 20 项主要预防研究中有 8 项、34 项次要预防研究中有 10 项、16 项治疗研究中有 6 项具有阳性结果。在主要预防研究中，有 8 项 RCT 中有 7 项具有阳性结果，这些 RCT 的参与者来自经常出现营养不良的人群。这些结果表明，应根据收益/风险比来分析抗氧化剂补充的潜在风险。
