Does vitamin D deficiency in asthma affect clinical and functional parameters? A Turkish multicenter study

Background: In recent years, interest in the effects of vitamin D on human health and the immune system has increased. Objective: This study aimed to investigate the relationship of vitamin D with asthma severity, attacks, and clinical and functional parameters in adult patients with asthma who were living in different geographic regions in Turkey. Methods: A total of 384 patients with stable asthma and 87 control subjects were included. A physical examination and a pulmonary function test were performed, and routine blood analyses and vitamin D levels were evaluated. Asthma Control Test was applied. The number of exacerbations in the previous year, asthma therapy, and medication adherence were recorded. Results: In our study, vitamin D levels were below the target values in both patients with asthma (median [minimum-maximum] 16.0 ng/mL [3.5-48 ng/ml]) and control subjects (median [minimum-maximum] 20.0 ng/mL [5.8-58.79 ng/mL]). However, it was lower in the patients with asthma than in the control subjects (p = 0.001). There was a negative relationship between the levels of vitamin D and the severity of asthma (Kendall τ = -0.146; p < 0.001). Furthermore, the patients with severe asthma were received The Global Initiative for Asthma (GINA) step 5 treatment showed significantly lower vitamin D compared with the patients who received GINA step 4 treatment (p = 0.037). Vitamin D levels correlated with forced vital capacity (FVC), forced expiratory volume in the first second of expiration (FEV₁), and peak expiratory flow (r, 0.221-0.236; p ≤ 0.001). In addition, a positive relationship was found between Asthma Control Test and vitamin D (r = 0.229; p = 0.001). However, body mass index (BMI), asthma exacerbation, and hospitalization were inversely related to vitamin D (r, 0.198-0.233; p = 0.001). Multivariable regression analysis revealed that FVC (p = 0.002), FEV₁ (p = 0.033), and BMI (p = 0.037) were independent determinants associated with vitamin D. Conclusion: This study suggested a high prevalence of vitamin D deficiency in adults with asthma living in different geographic areas in Turkey. Vitamin D deficiency is associated with asthma severity, poor control, and lower lung function.

The IL4-VNTR P1 Allele, IL4-VNTR P2P2 Genotype, and IL4-VNTR_IL6-174CG P2P1-GG Genotype Are Associated with an Increased Risk of Brucellosis

In this study, associations between IL-4, IL-6, and macrophage migration inhibitory factor (MIF) polymorphisms and susceptibility to brucellosis were investigated. Consecutive adult patients with no known treatment against brucellosis and who did not have any other autoimmune and/or chronic disorders, were included in this study (n = 120, Group I). Age and sex-matched controls who had no other autoimmune and/or chronic disorders were also included (n = 120, healthy volunteers, Group II). The IL4_P2P2 genotype, IL4_P1 allele, and IL4_variable number of tandem repeats (VNTR)_IL6-174CG compound genotype were found to be more frequent in the patient group than in control subjects. There were significant differences between the patients and controls with respect to the frequencies of the IL4_P2P2 genotype (77.5% versus 87.5%; p = 0.001; OR, 0.36; 95% confidence interval [CI], 0.21-0.62) and the IL4_P1 allele (12.1% versus 6.7%; p = 0.030; OR, 0.92; CI, 1.02-3.64). The IL4-VNTR_IL6-174CG compound genotype was also present at a significantly higher frequency in the patient group than in control subjects (11.7% versus 4.2%; p = 0.027, OR, 3.04; CI, 1.06-8.68). No statistically significant differences in the frequencies of the IL-6-174, MIF-173, IL-4_P1P1, and IL4_P2P1 genotypes were observed between patients and control subjects. The IL4_VNTR P1 allele, P2P2 genotypes, and IL4-VNTR_IL6-174CG P2P1-GG genotypes are common in southern Turkey, and carriers of these polymorphisms are susceptible to brucellosis.