Does serum vitamin D status reflect the severity of asthma? a comparative case control study

Objective: To determine the role of vitamin D in adult-onset asthma by estimating and comparing it with that of healthy controls and to associate it with lung function test. Methodology: This case control study was conducted in the Department of Physiology, University of Karachi. Cases were recruited from Jinnah Hospital. A total of 280 individuals were categorized into asthmatics and non-asthmatics. History of respiratory illness, D3 intake, drugs that alter serum D3, pregnant and lactating mothers were excluded from study. Asthmatics were included according to GINA guidelines. BMI, Spirometry, and serum 25(OH)2D estimation were performed. Statistically, results were analyzed by SPSS 21. Results: Difference of BMI and 25(OH)2D between two groups were statistically significant (p<0.001). Within controls, 47 had moderate and 93 had mild insufficiency. In cases, 40 mild asthmatics had moderate insufficiency and in moderate asthmatics, out of 50, 12 were severely and 38 were moderately insufficient of vitamin D. In severe asthmatics, 44 had severe while 6 had deficiency of vitamin D. Study revealed that 25 hydroxy D was directly proportional to FEV1 and FEV1/FVC in asthmatics (p<0.001). Conclusion: Vitamin D has pronounced effects on asthmatic condition by its immunomodulatory functions. Intake of this vitamin may improve the inflammation of airways and thus may affect the prognosis of asthma. (author)