Pediatrics：维生素D补充剂可降低儿童呼吸道感染的风险

最新一项研究证实儿童每天补充维生素D可减少在冬季患呼吸道感染的风险。相关研究论文发表在<em>Pediatrics</em>杂志上，研究揭示血液中维生素D水平的低的儿童补充维生素D能降低呼吸道感染风险。

麻省总医院（MGH）医学博士Carlos Camargo说：我们的随机对照试验表明，维生素D对呼吸道感染风险有重要影响，我们发现近250名血液中维生素D低的儿童在冬季每天服用维生素D补充剂能使得呼吸道感染的风险降低一半。

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最近的几项研究表明，维生素D主要作用是强健骨骼，此外还有免疫功能作用。Camargo和其他研究人员的研究维生素D水平较高与导致呼吸道感染如感冒或流感的风险降低相关联，但这样的观察性研究并不能证明维生素能防止感染的发生。这样的研究证据来自随机对照试验，具体就是比较两个相似的人群，要么接受或不接受干预措施如补充维生素D。第一个这样的试验在日本学童中间开展，其结果实模棱两可的，简而言之就是维生素D补充剂能导致某一种类型的流感风险降低，但并不会影响另一种类型，因此许多组织都要求进一步开展随机试验来解决上述问题。

该研究设计提供了强有力的证据表明低的维生素D和呼吸道感染有因果关系，维生素D水平低的儿童补充维生素D能防止一些呼吸道感染。研究人员指出，在这项研究中的维生素D剂量高于每日推荐剂量（每日300 IU），因为美国医学研究所提出儿童的推荐剂量为400 IU，其他研究团队推荐的每日剂量高达1,000 IU。

编译自：<a title="" href="http://www.sciencedaily.com/releases/2012/08/120820143906.htm" target="_blank">Vitamin D Supplementation Can Decrease Risk of Respiratory Infections in Children</a>

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<img src="http://www.bioon.com/biology/UploadFiles/201208/2012082209353725.jpg" alt="" width="115" height="150" />

<a title="" href="http://dx.doi.org/10.1542/peds.2011-3029" target="_blank">doi:10.1542/peds.2011-3029</a>
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<br/><strong>Randomized Trial of Vitamin D Supplementation and Risk of Acute Respiratory Tract Infection in Mongolia.</strong><br/>


Carlos A. Camargo Jr, Davaasambuu Ganmaa, A. Lindsay Frazier, Franca F. Kirchberg, Jennifer J. Stuart, Ken Kleinman, Nyamjav Sumberzul, and Janet W. Rich-Edwards.
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<p id="p-1"><br/><strong>OBJECTIVE:</strong><br/>
Observational studies suggest that serum levels of 25-hydroxyvitamin D (25[OH]D) are inversely associated with acute respiratory tract infections (ARIs). We hypothesized that vitamin D supplementation of children with vitamin D deficiency would lower the risk of ARIs.</p>

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<p id="p-2"><br/><strong>METHODS:</strong><br/>
By using cluster randomization, classrooms of 744 Mongolian schoolchildren were randomly assigned to different treatments in winter (January–March). This analysis focused on a subset of 247 children who were assigned to daily ingestion of unfortified regular milk (control; <em>n</em> = 104) or milk fortified with 300 IU of vitamin D₃ (<em>n</em> = 143). This comparison was double-blinded. The primary outcome was the number of parent-reported ARIs over the past 3 months.</p>

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<p id="p-3"><br/><strong>RESULTS:</strong><br/>
At baseline, the median serum 25(OH)D level was 7 ng/mL (interquartile range: 5–10 ng/mL). At the end of the trial, follow-up was 99% (<em>n</em> = 244), and the median 25(OH)D levels of children in the control versus vitamin D groups was significantly different (7 vs 19 ng/mL; <em>P</em> &lt; .001). Compared with controls, children receiving vitamin D reported significantly fewer ARIs during the study period (mean: 0.80 vs 0.45; <em>P</em> = .047), with a rate ratio of 0.52 (95% confidence interval: 0.31–0.89). Adjusting for age, gender, and history of wheezing, vitamin D continued to halve the risk of ARI (rate ratio: 0.50 [95% confidence interval: 0.28–0.88]). Similar results were found among children either below or above the median 25(OH)D level at baseline (rate ratio: 0.41 vs 0.57; <em>P</em>_interaction = .27).</p>

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<p id="p-4"><br/><strong>CONCLUSIONS:</strong><br/>
Vitamin D supplementation significantly reduced the risk of ARIs in winter among Mongolian children with vitamin D deficiency.</p>
<br/>来源：生物谷

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