Abstract

Calcitriol is the active form of Vitamin D. 7-Dehydrocholesterol in our skin gets converted to cholecalciferol when it is exposed to sunlight which gets hydroxylated in liver and kidney to finally form 1,25-DihydroxyCholecalciferol (Calcitriol) which is the active form of Vitamin D. The role of calcitriol in physiological and pathophysiological processes has been recognized only in the last couple of years. Research shows that calcitriol plays a role in several diseases involving the respiratory system. It plays an important role in immune regulation through interactions with vitamin D receptors (VDRs) expressed on airway immune cells. Higher calcitriol concentrations have been associated with better pulmonary function as measured by forced expiratory volume in 1 s (FEV₁) in a large cross-sectional study of the U.S. population in the National Health and Nutrition Examination Survey (NHANES) III.

Aim: The aim of the study was to assess and correlate serum vitamin D status with severity and degree of control of asthma.

Methods: Case control study was conducted in south Indian population with uncontrolled asthma/acute exacerbation of asthma. Serum 25 (OH) Vitamin D was estimated using an immunoassay method which was based on established spectrophotometric & automated procedures, approved by International Federation for Clinical Chemistry (IFCC) and pulmonary function test using a portable MIR winspiro spirobank II spirometer. Data were compared by using student ‘t’ test. Pearson’s correlation was done to see the association among vitamin D and pulmonary function test.

Results: Serum vitamin D levels were significantly lower in uncontrolled asthma/acute exacerbation of asthma. (p<0.05) Positive correlation of vitamin D with FEV₁ and FEV₁/FVC ratio is seen. (P value <0.05, r value 0.643 and p value <0.05, r value 0.714 respectively).

Conclusion: Vitamin D levels are significantly low in uncontrolled asthma. Asthmatics with a higher level of vitamin D have better pulmonary function and thereby a better quality of life.

Keywords: Vitamin D; Pulmonary function test; Adult asthmatics