Morris Cynthia D, Carson Susan
Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University Evidence-based Practice Center, 3181 SW Sam Jackson Park Road, Mail Code BICC, Portland, OR 97239, USA.
Ann Intern Med. 2003 Jul 1;139(1):56-70. doi: 10.7326/0003-4819-139-1-200307010-00014.
Antioxidant vitamins are thought to play a role in atherosclerosis. Supplementation of these nutrients has been explored as a means of reducing cardiovascular morbidity and mortality.
To assess the evidence of the effectiveness of vitamin supplementation, specifically vitamins A, C, and E; beta-carotene; folic acid; antioxidant combinations; and multivitamin supplements, in preventing cardiovascular disease.
Cochrane Controlled Trials Registry and MEDLINE (1966 to September 2001), reference lists, and experts.
The researchers selected English-language reports of randomized trials and cohort studies that assessed vitamin supplementation in western populations and reported incidence of or death from cardiovascular events. They also included reports of good- or fair-quality clinical trials of primary and secondary prevention and good- or fair-quality prospective cohort studies. Studies that examined only dietary nutrients or did not provide separate estimates for supplements were not included.
Two reviewers abstracted descriptive information and data on cardiovascular outcomes and mortality from included studies. The researchers assessed study quality using predetermined criteria.
Evidence tables were constructed to summarize data from included studies. The researchers summarized the strength, level, and quality of the overall evidence for the effectiveness of each of the vitamin supplements in preventing or treating cardiovascular disease.
Some good-quality cohort studies have reported an association between the use of vitamin supplements and lower risk for cardiovascular disease. Randomized, controlled trials of specific supplements, however, have failed to demonstrate a consistent or significant effect of any single vitamin or combination of vitamins on incidence of or death from cardiovascular disease. Understanding the sources of these differences will permit researchers to better analyze the cohort study data and to better design long-term clinical trials.
抗氧化维生素被认为在动脉粥样硬化中起作用。补充这些营养素已被探索作为降低心血管疾病发病率和死亡率的一种手段。
评估维生素补充剂，特别是维生素A、C和E；β-胡萝卜素；叶酸；抗氧化剂组合以及多种维生素补充剂在预防心血管疾病方面有效性的证据。
Cochrane对照试验注册库和MEDLINE（1966年至2001年9月）、参考文献列表以及专家。
研究人员选择了评估西方人群维生素补充情况并报告心血管事件发生率或死亡率的随机试验和队列研究的英文报告。他们还纳入了一级和二级预防的高质量或中等质量临床试验以及高质量或中等质量前瞻性队列研究的报告。仅研究膳食营养素或未提供补充剂单独估计值的研究未被纳入。
两名评审员从纳入研究中提取了描述性信息以及心血管结局和死亡率的数据。研究人员使用预定标准评估研究质量。
构建证据表以总结纳入研究的数据。研究人员总结了每种维生素补充剂在预防或治疗心血管疾病方面总体证据的强度、级别和质量。
一些高质量队列研究报告了使用维生素补充剂与较低心血管疾病风险之间的关联。然而，特定补充剂的随机对照试验未能证明任何单一维生素或维生素组合对心血管疾病发生率或死亡率有一致或显著的影响。了解这些差异的来源将使研究人员能够更好地分析队列研究数据并更好地设计长期临床试验。
