Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Pediatrics. 2012 Sep;130(3):e561-7. doi: 10.1542/peds.2011-3029. Epub 2012 Aug 20.
Observational studies suggest that serum levels of 25-hydroxyvitamin D (25[OH]D) are inversely associated with acute respiratory infections (ARIs). We hypothesized that vitamin D supplementation of children with vitamin D deficiency would lower the risk of ARIs.
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; n = 104) or milk fortified with 300 IU of vitamin D(3) (n = 143). This comparison was double-blinded. The primary outcome was the number of parent-reported ARIs over the past 3 months.
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% (n = 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; P < .001). Compared with controls, children receiving vitamin D reported significantly fewer ARIs during the study period (mean: 0.80 vs 0.45; P = .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; P(interaction) = .27).
Vitamin D supplementation significantly reduced the risk of ARIs in winter among Mongolian children with vitamin D deficiency.
观察性研究表明，血清 25-羟维生素 D（25[OH]D）水平与急性呼吸道感染（ARI）呈负相关。我们假设维生素 D 缺乏症患儿补充维生素 D 会降低 ARI 的风险。
通过使用集群随机化，744 名蒙古学童的教室在冬季（1 月至 3 月）被随机分配到不同的治疗组。本分析集中于 247 名被分配到每日摄入未经强化的普通牛奶（对照组；n = 104）或强化 300IU 维生素 D（3）的牛奶（n = 143）的儿童子集。这种比较是双盲的。主要结局是过去 3 个月内父母报告的 ARI 数量。
在基线时，血清 25（OH）D 水平的中位数为 7ng/mL（四分位距：5-10ng/mL）。在试验结束时，随访率为 99%（n = 244），对照组和维生素 D 组儿童的中位数 25（OH）D 水平差异显著（7 vs 19ng/mL；P<.001）。与对照组相比，接受维生素 D 的儿童在研究期间报告的 ARI 明显较少（平均值：0.80 与 0.45；P =.047），发生率比为 0.52（95%置信区间：0.31-0.89）。调整年龄、性别和喘息史后，维生素 D 仍将 ARI 的风险减半（发生率比：0.50[95%置信区间：0.28-0.88]）。在基线时血清 25（OH）D 水平低于或高于中位数的儿童中也发现了类似的结果（发生率比：0.41 与 0.57；P（交互）=.27）。
维生素 D 补充剂显著降低了蒙古维生素 D 缺乏症儿童冬季 ARI 的风险。
