Vitamin D and Asthma—Life After VIDA?

Abstract

The vitamin D hypothesis postulates that lower vitamin D levels are causally associated with increased asthma risk and asthma severity. Multiple epidemiological studies have shown an inverse relationship between circulating vitamin D levels (in the form of 25-hydroxy-vitamin D) and asthma severity and control, and lung function. However, in the recently published VIDA study, vitamin D supplementation failed to show an improvement in asthma control in adults. This article reviews the current epidemiological and trial evidence for vitamin D and asthma, and explores some of the possible alternative explanations for previous findings (including “reverse causation” and the importance of studying children and adults). We also address some of the unique challenges of conducting vitamin D trials, and potential ways to address them. Finally, I will argue for further clinical trials of vitamin D in asthma, especially in children, using knowledge gained from the VIDA trial.

Variable risk of atopic disease due to indoor fungal exposure in NHANES 2005–2006

“…For example, A. fumigatus and A. alternata are predominantly outdoor fungi, and their presence indoors relies on human activity and the transmission of spores into the home environment (in the absence of indoor dampness and better ventilation), which may explain why Alternaria was inversely associated with childhood nonallergic asthma (total IgE < 170 KU/L). There are other environmental exposures that may modify our findings such as vitamin D levels that may play a role in asthma pathogenesis [50]. Vitamin D levels may provide a protective effect against wheeze and asthma exacerbations [51].…”

Effects of Vitamin D Levels on Asthma Control and Severity in Children

“…D vitamini eksikliği, obezite, şehir hayatı gibi astım için sosyodemografik risk faktörleri arasında sayılmaktadır (2). D vitamininin %10'u gıdalar ile alınmakta %90'ı güneş ışı-ğındaki UV ile deride sentezlenmektedir (3).…”

Serum vitamin D status and biochemical parameters of asthmatic children in Sokoto Metropolis, North-western Nigeria

“…PTH increases with increase in asthma severity in order to stimulate the release of more vitamin D to combat the severity of asthma to a bearable minimum. 25 The finding of significantly increased serum levels of IgE among the asthmatic children compared with the controls also pinpoint the role of atopy in the expression of asthma in children in the study area. This finding is similar to the findings reported by previous researchers.…”

“…23 The findings in this study of increased serum levels of PTH among the asthmatic children was consistent with the previous studies. 21,24,25 The increased serum PTH may be explained by the compensatory mechanism of the body to maintain normal serum levels of vitamin D and calcium. PTH increases with increase in asthma severity in order to stimulate the release of more vitamin D to combat the severity of asthma to a bearable minimum.…”