Aggarwal Rakesh, Sentz John, Miller Mark A
Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Pediatrics. 2007 Jun;119(6):1120-30. doi: 10.1542/peds.2006-3481.
The quantified effect of zinc supplementation to prevent childhood diarrhea and respiratory illnesses is unclear. We conducted a meta-analysis of randomized, controlled trials on the subject.
We searched PubMed, Science Citation Index, and the Cochrane Database of Controlled Trials and hand-searched the reference lists of identified articles. All randomized, controlled trials of zinc supplementation for > or = 3 months for children < 5 years of age, using blinded assessment, were eligible. The outcome measures studied were number of episodes of illness, number of days with illness, and number of episodes of severe illness. Data from 17 studies were pooled by using random-effects and fixed-effects models for data with and without significant heterogeneity, respectively.
Children who received a zinc supplement had fewer episodes of diarrhea (rate ratio: 0.86) and respiratory tract infections (rate ratio: 0.92) and significantly fewer attacks of severe diarrhea or dysentery (rate ratio: 0.85), persistent diarrhea (rate ratio: 0.75), and lower respiratory tract infection or pneumonia (rate ratio: 0.80) than did those who received placebo. They also had significantly fewer total days with diarrhea (rate ratio: 0.86) but not days with respiratory illness (rate ratio: 0.95). Published studies showed a publication bias and significant heterogeneity; however, no cause for the latter could be identified.
Zinc supplementation reduced significantly the frequency and severity of diarrhea and respiratory illnesses and the duration of diarrheal morbidity. The relatively limited reduction in morbidity and the presence of significant heterogeneity and of publication bias indicate the need for larger, high-quality studies to identify subpopulations most likely to benefit.
锌补充剂预防儿童腹泻和呼吸道疾病的量化效果尚不清楚。我们对此主题进行了一项随机对照试验的荟萃分析。
我们检索了PubMed、科学引文索引和Cochrane对照试验数据库，并手工检索了已识别文章的参考文献列表。所有针对5岁以下儿童进行3个月及以上锌补充剂的随机对照试验，采用盲法评估，均符合条件。研究的结局指标为疾病发作次数、患病天数和严重疾病发作次数。分别使用随机效应模型和固定效应模型对17项研究的数据进行合并，用于分析有无显著异质性的数据。
与接受安慰剂的儿童相比，接受锌补充剂的儿童腹泻发作次数（率比：0.86）和呼吸道感染次数（率比：0.92）更少，严重腹泻或痢疾发作次数（率比：0.85）、持续性腹泻发作次数（率比：0.75）以及下呼吸道感染或肺炎发作次数（率比：0.80）显著减少。他们腹泻的总天数也显著减少（率比：0.86），但呼吸道疾病天数没有减少（率比：0.95）。已发表的研究显示存在发表偏倚和显著异质性；然而，无法确定后者的原因。
锌补充剂显著降低了腹泻和呼吸道疾病的频率和严重程度以及腹泻发病的持续时间。发病率的相对有限降低以及显著异质性和发表偏倚的存在表明，需要进行更大规模、高质量的研究，以确定最可能受益的亚人群。
