The Assessment of 25-Hydroxy Vitamin D Serum Level in Asthmatic Patients: A Case-Control Study

Background: The prevalence of vitamin D deficiency is increasing due to changes in lifestyle and dietary habits. The aim of this study was to compare the serum levels of 25-hydroxy vitamin D between patients with bronchial asthma and the healthy control group. Patients and Methods: In this case-control study, 45 patients with asthma and 45 healthy subjects were enrolled and the level of serum 25 (OH) vitamin D was measured in both groups. In addition, a welltrained observer assessed airway reversibility, peak flowmetry and spirometry in the participants. The data were statistically analyzed using t test, one-way analysis of variance (ANOVA), and chi-square test with Stata software (version 11). Results: The mean age (±SD) of participants were 49.06 ±16.43 and 46.13 ±16.10 years in case and control groups, respectively (P=.394). The prevalence of vitamin D deficiency was high in both groups (69% in case and 65.5% in control groups). The mean (±SD) serum 25 (OH) vitamin D was 16.24 (±14.98) ng/ml in case group and 17.70 (±16.07) ng/mL in control group (P=.657). We found a positive correlation between the levels of vitamin D and the amount of FEV1 (r=0.2). Conclusions: According to the present study, the mean serum levels of vitamin D differences were not statistically significant between asthmatic patients and control group. However, the results of this study showed a positive relationship between forced expiratory volumes in first second (FEV1) and vitamin D levels