Vitamin D to Prevent Severe Asthma Exacerbations in High-Risk Children - CCC

 描述(由申请人提供)：我们小组和其他人的观察性研究结果表明，维生素D缺乏(一种常见情况)与学龄儿童严重哮喘恶化的风险增加有关。我们假设，补充维生素D可降低6至14岁患有维生素D缺乏(血清25(OH)D&lt；30 ng/ml)且正在接受吸入皮质类固醇(ICS)治疗的轻度至中度持续性哮喘的高危儿童(定义为前一年病情恶化)的严重哮喘恶化的发生率。我们进一步假设，这种保护作用源于病毒感染发生率的降低，病毒感染导致这些儿童的严重哮喘加重和/或对ICS的反应增强。我们将在一项随机双掩蔽安慰剂对照临床试验中测试这一假设，主要和次要的具体目标如下：1)主要的具体目标1)确定维生素D3补充剂(每天4,000国际单位)在预防维生素D缺乏的高危学龄儿童和正在接受ICS治疗轻度至中度持续性哮喘的高危学龄儿童严重哮喘恶化方面是否优于安慰剂。针对患有维生素D缺乏的高危学龄儿童服用ICS治疗哮喘，以确定补充维生素D3是否在以下方面优于安慰剂：1)预防病毒感染导致的严重哮喘恶化2)减少ICS的每日剂量以及试验结束时ICS的平均累积剂量

 DESCRIPTION (provided by applicant): Findings from observational studies by our group and others suggest that vitamin D insufficiency (a common condition) is associated with an increased risk of severe asthma exacerbations in school-aged children. We hypothesize that vitamin D supplementation reduces the incidence of severe asthma exacerbations in high-risk (so defined due to an exacerbation in the previous year) children aged 6 to 14 years who have vitamin D insufficiency (a serum 25(OH) D <30 ng/ml) and who are being treated with inhaled corticosteroids (ICS) for mild to moderate persistent asthma. We further hypothesize that this protective effect results from a reduced incidence of viral infections that lead to severe asthma exacerbations and/or enhanced response to ICS in these children. We will test this hypothesis in a randomized double-masked placebo-controlled clinical trial with the following primary and secondary Specific Aims: Primary Specific Aim 1) To determine whether vitamin D3 supplementation (4,000 IU/day) is superior to placebo in preventing severe asthma exacerbations in high-risk school-aged children who have vitamin D insufficiency and who are on ICS for mild to moderate persistent asthma. Secondary Specific Aims In high-risk school-aged children with vitamin D insufficiency who are on ICS for asthma, to determine whether vitamin D3 supplementation is superior to placebo in: 1) Preventing severe asthma exacerbations resulting from viral infections 2) Reducing the daily dose of ICS as well as the average cumulative dose of ICS, at the end of the trial