Vitamin D and Bronchial Asthma: An Overview of Data From the Past 5 Years

Abstract

Vitamin D is a potent immunomodulator capable of dampening inflammatory signals in several cell types involved in the asthmatic response. Its deficiency has been associated with increased inflammation, exacerbations and overall worse outcomes in patients with asthma. Given the increase in the prevalence of asthma over the last few decades, there has been enormous interest in the use of vitamin D supplementation as a potential therapeutic option. Several studies have found that low serum levels of vitamin D (< 20 ng/ml) are associated with increased exacerbations, increased airway inflammation, decreased lung function and poor prognosis in asthmatic patients. Results from the in vitro and in vivo studies in animals and human have suggested that supplementation with vitamin D can ameliorate several hallmark features of asthma. However, the findings obtained from clinical trials are controversial and do not unequivocally support the beneficial role of vitamin D in asthma. Largely, interventional studies in children, pregnant women and adults have primarily found little-to-no effect of vitamin D supplementation on improved asthma symptoms, onset or progression of the disease. This could be related to the severity of the disease process and other confounding factors. Despite the conflicting data obtained from clinical trials, vitamin D deficiency does influence the inflammatory response in the airways. Further studies are needed to determine the exact mechanisms by which vitamin D supplementation may induce anti-inflammatory effects. Here, we critically reviewed the most recent findings from in vitro studies, animal models, and clinical trials regarding the role of vitamin D in bronchial asthma.

Can Vitamin D Help in Achieving Asthma Control? Vitamin D “Revisited”: An Updated Insight

“…All of preschoolers in the study group (100% of the subjects) had level of ≥ 75 nmol/L (> 30 ng/mL) serum 25(OH)D after 3 months of supplementation [5,25]. Similarly, supplementation of 2000 IU/d vitamin D for 15 weeks lead to an increased level of serum 25(OH)D and a reduced number of asthma-related missed schooldays in children from Ireland.…”

“…Nowadays, recommended doses of vitamin D for fortification of food are not sufficient and adequate for prevention of vitamin D deficiency and insufficiency. Additionally, there are other factors that may affect the levels of 25(OH)D in the serum, such as sex, race, single nucleotide polymorphisms (SNPs) in VDRs and VDBPs and pharmacogenic factors in metabolism of vitamin D [5].…”

Association of group‐specific component exon 11 polymorphisms with bronchial asthma in children and adolescents

“…Several factors could affect serum vitamin D levels, including race, binding proteins, sex and single nucleotide polymorphisms (SNPs) in VDR and VDBP and other pharmacogenetic factors in vitamin D metabolic pathways . VDBP is encoded by the GC (group‐specific component) gene located at 4q11‐13 .…”

Vitamina D y asma en la práctica clínica: el impacto en el control del asma

“…2,3 On the other hand, the control of asthma is the cornerstone strategy in the management of patients with asthma as stated by the Global Initiative for Asthma (GINA) document. 4 The asthma control evaluation is based on a global assessment of respiratory symptoms, lung function, bronchial inflammation, comorbidity (including obesity, upper airways disorders, gastroesophageal reflux, emotional problems, nocturnal apnea), risk factors, compliance, and adherence to treatments.…”