METHODS: Systematic review and meta-analysis. Two reviewers independently assessed studies for inclusion. Data were double extracted; discrepancies were resolved by discussion. Meta-analyses were performed for mortality, illness, vision, and side effects.
METHODS: Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Medline, Embase, Global Health, Latin American and Caribbean Health Sciences, metaRegister of Controlled Trials, and African Index Medicus. Databases were searched to April 2010 without restriction by language or publication status.
METHODS: Randomised trials of synthetic oral vitamin A supplements in children aged 6 months to 5 years. Studies of children with current illness (such as diarrhoea, measles, and HIV), studies of children in hospital, and studies of food fortification or β carotene were excluded.
RESULTS: 43 trials with about 215,633 children were included. Seventeen trials including 194,483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91). Vitamin A supplementation was associated with a reduced incidence of diarrhoea (0.85, 0.82 to 0.87) and measles (0.50, 0.37 to 0.67) and a reduced prevalence of vision problems, including night blindness (0.32, 0.21 to 0.50) and xerophthalmia (0.31, 0.22 to 0.45). Three trials reported an increased risk of vomiting within the first 48 hours of supplementation (2.75, 1.81 to 4.19).
CONCLUSIONS: Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias. Further placebo controlled trials of vitamin A supplementation in children between 6 and 59 months of age are not required. However, there is a need for further studies comparing different doses and delivery mechanisms (for example, fortification). Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries.
方法:系统评价和荟萃分析。两名审稿人独立评估纳入研究。数据被双重提取;差异通过讨论得到解决。对死亡率进行了荟萃分析,疾病,愿景,和副作用。
方法:Cochrane图书馆的Cochrane中央对照试验登记册(CENTRAL),Medline,Embase,全球卫生,拉丁美洲和加勒比健康科学,受控试验的元注册,和非洲指数药物。数据库搜索到2010年4月,没有语言或出版状态的限制。
方法:6个月至5岁儿童合成口服维生素A补充剂的随机试验。对患有当前疾病(例如腹泻,麻疹,和艾滋病毒),对住院儿童的研究,食品强化或β-胡萝卜素的研究被排除在外。
结果:纳入43项试验,约215,633名儿童。包括194,483名参与者在内的17项试验报告了全因死亡率降低了24%(比率=0.76,95%置信区间为0.69至0.83)。7项试验报告与腹泻相关的死亡率降低了28%(0.72,0.57至0.91)。补充维生素A与腹泻(0.85,0.82至0.87)和麻疹(0.50,0.37至0.67)的发病率降低以及视力问题的患病率降低有关。包括夜盲症(0.32,0.21至0.50)和干眼症(0.31,0.22至0.45)。3项试验报告了在补药的前48小时内呕吐的风险增加(2.75,1.81至4.19)。
结论:补充维生素A可显著降低死亡率,发病率,以及一系列环境中的视力问题,这些结果不能用偏差来解释。不需要在6至59个月大的儿童中补充维生素A的进一步安慰剂对照试验。然而,需要进一步研究比较不同的剂量和递送机制(例如,设防)。在其他来源可用之前,维生素A补充剂应给予所有有缺乏风险的儿童,特别是在低收入和中等收入国家。