Related Experiment Video
Updated: May 14, 2026

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels
Published on: August 7, 2017
Prospective association of 25-hydroxyvitamin d3 and d2 with childhood lung function, asthma, wheezing, and flexural
Anna-Maija Tolppanen1, Adrian Sayers, Raquel Granell
1MRC Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK. anna-maija.tolppanen@uef.fi
Background:
Higher serum total 25-hydroxyvitamin D (25(OH)D) concentrations have been associated with better lung function and lower risk of allergic disease. 25(OH)D3 constitutes the majority of total 25(OH)D and has been suggested to be more potent than 25(OH)D2. We studied the prospective associations of 25(OH)D2 and 25(OH)D3 with asthma, wheezing, flexural dermatitis, and lung function in children who participated in the Avon Longitudinal Study of Parents and Children-a population-based contemporary birth cohort of children born in 1991-1992 from South West England.
Methods:
Serum 25(OH)D2 and 25(OH)D3 concentrations, measured at a mean age of 9.8 years, were related to incident cases of wheezing (study sample: n = 3,323, 141 cases; 4%), asthma (n = 3,323, 464 cases; 14%), and flexural dermatitis (n = 3,748, 300 cases; 8%), as well as lung function (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and mid-forced expiratory flow assessed at a mean age of 15.5 years: n = 2,259).
Results:
25(OH)D2 was inversely associated with flexural dermatitis (adjusted odds ratio per doubling of exposure = 0.83 [95% confidence interval = 0.72-0.94]) and wheezing (0.83 [0.68-1.00]), and 25(OH)D3 was positively associated with flexural dermatitis (1.09 [1.00-1.18]) and wheezing (1.14 [1.03-1.28]). 25(OH)D2 was weakly positively associated with FEV1, and FVC. 25(OH)D3 was not associated with lung function.
Conclusions:
These results suggest that higher 25(OH)D3 concentrations are associated with increased risk of wheezing and flexural dermatitis. Despite being one of the few prospective studies and being able to adjust for confounders, these findings need replication. Our results do not provide strong evidence that lower concentrations of vitamin D are detrimental to respiratory and allergic health in children.
Related Concept Videos
Asthma I: Introduction
Asthma III: Clinical Manifestations
Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
Asthma-II: Pathophysiology and Classification
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
Asthma-I: Introduction
Asthma: Pathogenesis and Management
Asthma is classified as allergic and non-allergic. Allergens such as dust mites, pollen, and pet dander trigger allergic asthma, while factors like cold air, intense emotions, or exercise can induce non-allergic asthma.
