« Previous Next »The Journal of Allergy and Clinical Immunology
Volume 125, Issue 5 , Pages 995-1000, May 2010

Decreased serum vitamin D levels in children with asthma are associated with increased corticosteroid use

Daniel A. Searing, MD
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Health, Denver, Colo
Yong Zhang, PhD
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Health, Denver, Colo
James R. Murphy, PhD
- Division of Biostatistics and Bioinformatics, National Jewish Health, Denver, Colo
- Department of Preventive Medicine and Biometrics, University of Colorado Denver, Aurora, Colo
Pia J. Hauk, MD
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Health, Denver, Colo
- Department of Pediatrics, University of Colorado Denver, Aurora, Colo
Elena Goleva, PhD
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Health, Denver, Colo
Donald Y.M. Leung, MD, PhD
- Division of Allergy and Immunology, Department of Pediatrics, National Jewish Health, Denver, Colo
- Department of Pediatrics, University of Colorado Denver, Aurora, Colo
- Reprint requests: Donald Y. M. Leung, MD, PhD, Division of Pediatric Allergy and Immunology, National Jewish Health, 1400 Jackson St, K926i, Denver, CO 80206.

Received 23 December 2009; received in revised form 8 February 2010; accepted 15 March 2010. published online 12 April 2010.

Background

There is little knowledge about clinical variables associated with vitamin D (VitD) insufficiency in asthmatic children.

Objective

We sought to investigate disease variables associated with VitD insufficiency in patients with childhood asthma and interaction of VitD with corticosteroid-mediated anti-inflammatory responses.

Methods

We analyzed 25-hydroxyvitamin D serum levels in 100 asthmatic children to investigate relationships between 25-hydroxyvitamin D levels and patients' characteristics. We determined VitD's effects on dexamethasone (DEX) induction of mitogen-activated protein kinase phosphatase 1 and IL-10 in PBMCs.

Results

The median 25-hydroxyvitamin D serum level was 31 ng/mL. Forty-seven percent of subjects had VitD levels in the insufficient range (<30 ng/mL), whereas 17% were VitD deficient (<20 ng/mL). Log10 IgE (P = .01, ρ = −0.25) and the number of positive aeroallergen skin prick test responses (P = .02, ρ = −0.23) showed a significant inverse correlation with VitD levels, whereas FEV1 percent predicted (P = .004, ρ = 0.34) and FEV1/forced vital capacity ratio (P = .01, ρ = 0.30) showed a significant positive correlation with VitD levels. The use of inhaled steroids (P = .0475), use of oral steroids (P = .02), and total steroid dose (P = .001) all showed significant inverse correlations with VitD levels. The amount of mitogen-activated protein kinase phosphatase 1 and IL10 mRNA induced by VitD plus DEX was significantly greater than that induced by DEX alone (P < .01). In an experimental model of steroid resistance in which DEX alone did not inhibit T-cell proliferation, addition of VitD to DEX resulted in significant dose-dependent suppression of cell proliferation.

Conclusions

Corticosteroid use and worsening airflow limitation are associated with lower VitD serum levels in asthmatic patients. VitD enhances glucocorticoid action in PBMCs from asthmatic patients and enhances the immunosuppressive function of DEX in vitro.

Key words: Vitamin D, children, asthma

Abbreviations used: DEX, Dexamethasone, FVC, forced vital capacity, ICS, inhaled corticosteroid, MKP-1, mitogen-activated protein kinase phosphatase 1, TSST, toxic shock syndrome toxin, VitD, vitamin D