The Role of Vitamin D on The Clinical Course of Adult Asthma

Abstract

Background: Besides skeletal functions, it has been speculated that vitamin D (vitD) is involved in the pathogenesis of pulmonary diseases. Little is known about vitD in adult asthma or its association with asthma severity and control. As previous studies are inconclusive, the purpose of this study was to determine the prevalance of vitD deficiency in adult asthma and to investigate associations of serum vitD levels with atopy, asthma, and lung function. Material and Method: 112 (88 stable and 24 exacerbated) asthma patients and similar 94 healthy adults evaluated in this cross-sectional study. Detailed demographic data and clinical features, pulmonary function tests of all participants were recorded. Serum 25(OH)D3 has been analyzed with high pressure liquid chromotography technique. Serum vitD levels ?20 ng/ml has been accepted as vitD deficiency. Results: The mean serum vitD level was 25.19 ± 12.01 and 27.09 ± 12.9 ng/ml in asthma and the control group respectively (p:0.27). The prevalance of vitD deficiency and the mean serum vitD level were similar in stable asthma group, exacerbated asthma group and the control group (respectively p:0.398, p:0.363). Serum vitD levels of female participants (23.89 ± 11.92 ng / ml) was significantly lower than males in asthmatics (29.52 ± 11.48 ng / ml) (p:0.03). Forced expiratory volume in first second (FEV1) and forced vital capacity (FVC) were significantly lower in the vitD deficient group in both asthmatic and control group (respectively in patients p:0.003, p:0.01, in control group p:0.04, p:0.005). In stable asthma (n=88), mean serum vitD level of obese (22.8±13.3 ng/ml) was significantly lower than non-obese patients (27.9±11.2 ng/ml)(p:0.024) and body mass index and serum vitD levels were negatively correlated (p:0.02). Conclusion: The serum vitD levels and vitD deficiency of asthmatics were not different from control group, but significantly associated with female gender, poor lung function and obesity.