Abstract

Background: The deficiency of vitamin D has been associated with an increased risk of asthma. However, its relation with asthma severity or prognosis is not yet established especially among adults.
Methodology: The cross-sectional study included 162 Saudi adults with bronchial asthma selected by a non-probability consecutive sampling from Ibn Sina National College Hospital in Jeddah, Saudi Arabia from December 2017 to February 2018. Data were collected using a structured questionnaire and a baseline spirometry. Assessment of asthma control test (ACT) was done according to GINA (Global Initiative for Asthma) guidelines. The 25-hydroxyvitamin D 25(OH) D) was analyzed using enzyme-linked immunosorbent assay (ELISA) test.
Results: The patients had a median ACT score of 19 (partially controlled asthma) with 48.1% controlled asthma and 22% increased the risk of future exacerbations. The median 25(OH) D was deficient (31.18nmol/L) (34% insufficiency and 66% deficiency). There was a significant positive correlation between vitamin D and ACT (r=0.91, p=0.000). Asthmatics with future exacerbation had lower 25(OH) D level (p=0.000) with more prevalence vitamin D deficiency (94.4%)
Conclusion: Saudi adults with partially uncontrolled asthma had deficient vitamin D level especially those at risk of future exacerbation. The association between ACT and vitamin D in the absence of any association with respiratory function could reflect the importance of low vitamin D as a marker of severity. Further clinical trials are needed to explore the possible cause and effect relationship.

Key words: Vitamin D, 25-hydroxy Vitamin D, asthma, ACT