Serum 25-hydroxyvitamin D levels do not correlate with asthma severity in a case-controlled study of children and adolescents

Abstract

Background: There is no consensus on the association between vitamin D and asthma. Objective: To determine the relationship between 25-hydroxyvitamin D [25(OH)D] levels and asthma symptom severity in children and adolescents. Methods: A retrospective, case-control study of 263 subjects of ages 2 -19 years with asthma who were compared to 284 non-asthmatic controls of similar ages. Subjects were excluded if they had diseases of calcium or vitamin D metabolism or were receiving calcium or vitamin D supplementation. Serum 25(OH)D was measured in all subjects. Asthma symptom severity, usually stratified into 6 steps, was stratified into five steps [1 -5] based on the number and dose of controller medications used as outlined by the National Heart, Lung, and Blood Institute ' s guidelines. Mean 25(OH)D values were compared between the asthmatic patients and controls, as well as among the five steps of asthma symptom severity. Results were adjusted for age, sex, BMI, race and severity of asthma symptoms. Results: There was no difference in 25(OH)D between asthmatic patients and controls (28.64 ± 10.09 vs. 28.42 ± 11.47, p = 1.0). However, there was a significant difference in 25(OH)D between obese and non-obese asthmatic patients (23.33 ± 7.67 vs. 30.16 ± 10.20, p < 0.0001), as well as obese and non-obese controls (24.56 ± 9.90 vs. 29.50 ± 11.66, p = 0.003). Mean 25(OH)D levels did not vary significantly among the five steps of asthma symptom severity. Conclusions: There were no differences in mean 25(OH) D levels between asthmatic patients and controls. Mean 25(OH)D level was significantly lower in both the obese asthmatic patients and obese controls. Asthma severity had no relationship to mean 25(OH)D levels.

Vitamin D Levels of Asthmatic Children with and Without Obesity

“…In a study, the frequency of vitamin D deficiency (54%) or insufficiency (86%) in 92 African-American asthmatic children aged 6-20 years was found to be higher than in healthy controls (18). However, there are other studies that did not find a difference in Vitamin D levels between patients with and without asthma (8,(13)(14)(15). In accordance with these reports, serum vitamin D levels were similar in patients with and without asthma in our study.…”

“…The generally low levels may have prevented appropriate statistical analysis. Menon et al also did not find a relation between vitamin D levels and asthma severity but 75.7% of patients had mild asthma (15). Similar to that study, nearly 89% had mild asthma in our study and this may have affected the results.…”

“…claimed no relationship between asthma and vitamin D levels (8,14,15,18). As a matter of fact this was the case in our study as vitamin D deficiency was present in 97.5% and insufficiency was present in 2.5% of our study group and Vitamin D levels did not differ between patients with and without asthma.…”

“…In birth cohorts, maternal vitamin D and cord blood level of vitamin D are reported to be inversely associated with asthma (12,13). However, in some studies evaluating adolescent patients, serum vitamin D levels were not found to be different between subjects with or without asthma (14,15).…”

Effects of Vitamin D Levels on Asthma Control and Severity in Children

“…Bazı kesitsel çalışmalarda serum D vitamini düzeylerinin astımlı çocuklarda sağlıklı çocuklara göre daha düşük olduğu (4,(10)(11)(12) sınırlı sayıdaki çalışmada serum D vitamini düzeylerindeki yüksekliğinin astım riskinde artmaya neden olduğu gösterilmiştir (13,14). Bazı çalışmalarda ise bu farklılıklar gözlenmemiştir (15)(16)(17)(18)(19). D vitamini ve günümüzdeki astım rehberlerinde astım tedavisinin ana amacı olarak ifade edilen astım kontrolü ilişkili yapılmış sınırlı sayıda çalışma vardır.…”