Double-blind randomised placebo-controlled trial of bolus-dose vitamin D3 supplementation in adults with asthma (ViDiAs).
BACKGROUND
Asthma exacerbations are commonly precipitated by viral upper respiratory infections (URIs). Vitamin D insufficiency associates with susceptibility to URI in patients with asthma. Trials of vitamin D in adults with asthma with incidence of exacerbation and URI as primary outcome are lacking.


OBJECTIVE
To conduct a randomised controlled trial of vitamin D3 supplementation for the prevention of asthma exacerbation and URI (coprimary outcomes).


METHODS
250 adults with asthma in London, UK were allocated to receive six 2-monthly oral doses of 3 mg vitamin D3 (n=125) or placebo (n=125) over 1 year. Secondary outcomes included asthma control test and St George's Respiratory Questionnaire scores, fractional exhaled nitric oxide and concentrations of inflammatory markers in induced sputum. Subgroup analyses were performed to determine whether effects of supplementation were modified by baseline vitamin D status or genotype for 34 single nucleotide polymorphisms in 11 vitamin D pathway genes.


RESULTS
206/250 participants (82%) were vitamin D insufficient at baseline. Vitamin D3 did not influence time to first severe exacerbation (adjusted HR 1.02, 95% CI 0.69 to 1.53, p=0.91) or first URI (adjusted HR 0.87, 95% CI 0.64 to 1.16, p=0.34). No clinically important effect of vitamin D3 was seen on any of the secondary outcomes listed above. The influence of vitamin D3 on coprimary outcomes was not modified by baseline vitamin D status or genotype.


CONCLUSIONS
Bolus-dose vitamin D3 supplementation did not influence time to exacerbation or URI in a population of adults with asthma with a high prevalence of baseline vitamin D insufficiency.


BACKGROUND
NCT00978315 (ClinicalTrials.gov).
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK Asthma UK Centre for Applied Research, Blizard Institute, Queen Mary University of London, London, UK.
Adrian R
AR
Martineau
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Beverley D
BD
MacLaughlin
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Richard L
RL
Hooper
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK Asthma UK Centre for Applied Research, Blizard Institute, Queen Mary University of London, London, UK.
Neil C
NC
Barnes
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
David A
DA
Jolliffe
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Claire L
CL
Greiller
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Kate
K
Kilpin
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
David
D
McLaughlin
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Gareth
G
Fletcher
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Charles A
CA
Mein
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Mimoza
M
Hoti
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Robert
R
Walton
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Jonathan
J
Grigg
Homerton University Hospital, London, UK.
Peter M
PM
Timms
Homerton University Hospital, London, UK.
Raj K
RK
Rajakulasingam
Homerton University Hospital, London, UK.
Angshu
A
Bhowmik
Homerton University Hospital, London, UK.
Marion
M
Rowe
Homerton University Hospital, London, UK.
Timothy R
TR
Venton
Queen's Hospital, Rom Valley Way, Romford, London, UK.
Aklak B
AB
Choudhury
Royal London Hospital, London, UK.
David E
DE
Simcock
London School of Hygiene and Tropical Medicine, London, UK.
Zia
Z
Sadique
NIHR Leicester Respiratory Biomedical Research Unit, Glenfield Hospital, Leicester, UK.
William R
WR
Monteiro
MRC and the Asthma UK Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
Christopher J
CJ
Corrigan
MRC and the Asthma UK Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
Catherine M
CM
Hawrylowicz
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK Asthma UK Centre for Applied Research, Blizard Institute, Queen Mary University of London, London, UK MRC and the Asthma UK Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
Christopher J
CJ
Griffiths
D000328:Adult; D001249:Asthma / Q000150:complications* / Q000517:prevention & control*; D002762:Cholecalciferol / Q000008:administration & dosage*; D015331:Cohort Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000517:prevention & control*; D013997:Time Factors; D014815:Vitamins / Q000008:administration & dosage*
D014815:Vitamins; D002762:Cholecalciferol
Asthma; Respiratory Infection; Viral infection