A Daily 5000 IU Vitamin D Supplement for the Improvement of Lung Function and Asthma Control in Adults With Asthma: a Randomised Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 32
- 试验地点
- 2
- 主要终点
- Change in lung function from baseline to 12 weeks
研究概览
简要总结
Asthma is a disease characterised by chronic inflammation of the airways leading to symptoms including periods of shortness of breath, wheezing and a tight chest due to airway narrowing in affected patients. Current data show that one in 12 adults are currently receiving treatment for asthma in the United Kingdom (UK), with the UK having some of the highest rates in Europe. In the winter, 30-40% of the UK population are vitamin D deficient with some asthma patients having significantly lower vitamin D levels compared to normal patients. Vitamin D has been shown to be involved in the development of immune-related disorders including asthma. Cross-sectional research has shown that reduced vitamin D levels are associated with reduced lung function, increased airway hyper-responsiveness and reduced response to glucocorticoids, suggesting vitamin D levels may also implicate asthma treatment. To date, there have been three randomised controlled trials (RCT) assessing the effect of vitamin D supplementation in adults with symptomatic asthma. These trials have not found a significant effect of vitamin D supplementation on asthma. However, these studies relied on high doses of vitamin D with long time periods between doses. There is a requirement for RCTs in adults with daily supplementation of lower doses of vitamin D as it has been suggested that daily supplementation is more effective for inducing non-classical actions of vitamin D. However, vitamin D has been found to significantly improve airway function as measured by forced expiratory volume in one second (FEV1) in adults supplemented with 100, 000 international units (IU) vitamin D intramuscularly plus 50, 000 IU oral vitamin D weekly. Therefore, the effect of daily dosing on lung function also requires investigation. Furthermore, these trials have focussed on clinical outcomes without investigating the cellular mechanisms affording protection.
详细描述
Recruitment and sampling strategy:
Participants will be recruited from the University of Chester (staff and students) and surrounding areas, United Kingdom (UK) only. Emails, posters and social media will be used to advertise the study to the target group (adults with asthma). A total of 28 adults with asthma aged 18-65 years old will be included in the study based on criteria described below. Eligibility will be based upon previous diagnosis of asthma by a general practitioner (GP) and the number of times asthma medication is required at screening before the start of the study. Participants will be required to complete a screening questionnaire which will provide information about participant's health status, drugs/medication/supplement usage and sun exposure. Those that have had asthma diagnosed by a GP and require their medication more than twice per week will be included. All eligible participants will be briefed on the study protocol before the beginning of the study, and the eligible participants will be given a participant information sheet (PIS) and asked to provide written informed consent.
A 12 week, double blind, randomised controlled trial will be carried out in the clinical laboratory at The University of Chester, UK. Most vitamin D and asthma studies have used supplement concentrations up to 120, 000 international units (IU) with no adverse effects. The European Food Standards Agency (EFSA) set a no-observed-adverse-effect-level (NOAEL) of 10,000IU/day (COT, 2015).
Participants will be randomly allocated to 2 groups:
- vitamin D group
- placebo group
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Males or females aged 18 years to 65 years
- •Asthma diagnosed by a general practitioner
- •Taking inhaled therapy to treat asthma that is required at least two times per week
排除标准
- •Taking vitamin D supplements or supplements containing calcium
- •History of asthma requiring treatment with intubation and mechanical ventilation within the past five years
- •Require inhaled asthma therapy more than four times per day
- •Respiratory tract infection within the past four weeks
- •Suffering from chronic diseases of the lung (other than asthma), heart, liver, kidney, endocrine or nervous system or immunodeficiency
- •History of smoking within the past year or > 10 years total
- •Been on a sun holiday within a month of taking part in the study or during the study. For the purpose of this study a sun holiday is defined as: spending one week or more in a hotter climate with the intention of sun-bathing
- •Unable to communicate in English
结局指标
主要结局
Change in lung function from baseline to 12 weeks
时间窗: 0 weeks, 6 weeks, 12 weeks
Forced expiratory volume in one second (FEV1) and forced expiratory volume (FVC) measured by spirometry
次要结局
- Change in C-reactive protein (CRP) concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in immunoglobulin E (IgE) concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in interleukin-(IL)4 concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in IL-10 concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in IL-13 concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in Full Blood Count Concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in interferon-gamma (IFN-ϒ) concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in tumour-necrosis-factor-alpha (TNF-α) concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in Asthma Control Test™ score(0 weeks, 6 weeks, 12 weeks)
- Change in vitamin D concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)
- Change in parathyroid hormone (PTH) concentration from baseline to 12 weeks(0 weeks, 6 weeks, 12 weeks)