1. Prevalence, determinants and clinical correlates of vitamin D deficiency in adults with inhaled corticosteroid-treated asthma in London, UK.
- Author
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Jolliffe DA, Kilpin K, MacLaughlin BD, Greiller CL, Hooper RL, Barnes NC, Timms PM, Rajakulasingam RK, Bhowmik A, Choudhury AB, Simcock DE, Hyppönen E, Corrigan CJ, Walton RT, Griffiths CJ, and Martineau AR
- Subjects
- Administration, Inhalation, Adolescent, Adrenal Cortex Hormones therapeutic use, Adult, Aged, Anti-Asthmatic Agents therapeutic use, Asthma blood, Asthma complications, Asthma drug therapy, Body Mass Index, Cross-Sectional Studies, Cytochrome P-450 Enzyme System blood, Cytochrome P-450 Enzyme System genetics, DNA-Binding Proteins blood, DNA-Binding Proteins genetics, Eosinophils metabolism, Eosinophils pathology, Female, Gene Expression Regulation, Humans, London epidemiology, Low Density Lipoprotein Receptor-Related Protein-2 blood, Low Density Lipoprotein Receptor-Related Protein-2 genetics, Male, Middle Aged, Oxidoreductases Acting on CH-CH Group Donors blood, Oxidoreductases Acting on CH-CH Group Donors genetics, Racial Groups, Receptors, Calcitriol blood, Receptors, Calcitriol genetics, Receptors, Cell Surface blood, Receptors, Cell Surface genetics, Respiratory Function Tests, Severity of Illness Index, Transcription Factors blood, Transcription Factors genetics, Vitamin D blood, Vitamin D Deficiency blood, Vitamin D Deficiency complications, Vitamin D Deficiency drug therapy, Asthma epidemiology, Vitamin D analogs & derivatives, Vitamin D Deficiency epidemiology
- Abstract
Vitamin D deficiency is common in children with asthma, and it associates with poor asthma control, reduced forced expiratory volume in one second (FEV
1 ) and increased requirement for inhaled corticosteroids (ICS). Cross-sectional studies investigating the prevalence, determinants and clinical correlates of vitamin D deficiency in adults with asthma are lacking. We conducted a multi-centre cross-sectional study in 297 adults with a medical record diagnosis of ICS-treated asthma living in London, UK. Details of potential environmental determinants of vitamin D status, asthma control and medication use were collected by questionnaire; blood samples were taken for analysis of serum 25(OH)D concentration and DNA extraction, and participants underwent measurement of weight, height and fractional exhaled nitric oxide concentration (FeNO), spirometry and sputum induction for determination of lower airway eosinophil counts (n=35 sub-group). Thirty-five single nucleotide polymorphisms (SNP) in 11 vitamin D pathway genes (DBP, DHCR7, RXRA, CYP2R1, CYP27B1, CYP24A1, CYP3A4 CYP27A1, LRP2, CUBN, VDR) were typed using Taqman allelic discrimination assays. Linear regression was used to identify environmental and genetic factors independently associated with serum 25(OH)D concentration, and to determine whether vitamin D status was independently associated with Asthma Control Test (ACT) score, ICS dose, FeNO, forced vital capacity (FVC), FEV1 or lower airway eosinophilia. Mean serum 25(OH)D concentration was 50.6nmol/L (SD 24.9); 162/297 (54.5%) participants were vitamin D deficient (serum 25(OH)D concentration <50nmol/L). Lower vitamin D status was associated with higher body mass index (P=0.014), non-White ethnicity (P=0.036), unemployment (P for trend=0.012), lack of vitamin D supplement use (P<0.001), sampling in Winter or Spring (P for trend <0.001) and lack of a recent sunny holiday abroad (P=0.030), but not with potential genetic determinants. Vitamin D status was not found to associate with any marker of asthma control investigated. Vitamin D deficiency is common among UK adults with ICS-treated asthma, and classical environmental determinants of serum 25(OH)D operate in this population. However, in contrast to studies conducted in children, we found no association between vitamin D status and markers of asthma severity or control., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)- Published
- 2018
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