A Relationship between Asthma and Vitamin D

Abstract

Background: Vit D is a micronutrient that plays numerous roles in terms of homeostasis, physiology and immunomodulation. The aim of this study was to investigate a relationship between vit D levels and asthma control. Objectives: We describe the vit D level among an out-patient asthma population in Gauteng, South Africa. Our primary objective was to compare vit D levels between controlled and uncontrolled asthmatic patients and secondarily to estimate the prevalence of vit D deficiency and insufficiency among asthma patients, and to compare vit D levels amongst patients using different therapies (dose of steroid) for asthma. Methods: A prospective, cross-sectional descriptive study using questionnaire, clinical record review and blood results was conducted at Chris Hani Baragwanath Academic Hospital from March 2020 to 30th June 2022. Vit D levels were measured using a double sandwich immunoassay using a chemiluminescent label. Results: The sample was predominantly female, African, a median age of 52 years, and a mean vit D level was 24.2ng/ml. Only 19% of the cohort had controlled asthma. The prevalence of vit D insufficiency and deficiency were 41% and 35 % respectively, with no significant difference in mean vit D level between the controlled and uncontrolled asthma groups. There were 2 independent predictors of severe disease: the presence of eczema; and increasing waist circumference. There was no difference in terms of vit D levels among asthmatic patients using oral or inhaled corticosteroids in our study. Conclusion: The main finding was the absence of significant difference in the median vit D levels between controlled and uncontrolled asthmatics.