October 3, 2017
Queen Mary University of London
oral vitamin D supplements in addition to standard asthma medication could
halve the risk of asthma attacks requiring hospital attendance, according to
Taking oral vitamin D
supplements in addition to standard asthma medication could halve the risk of
asthma attacks requiring hospital attendance, according to research led by
Queen Mary University of London (QMUL).
Asthma affects more than
300 million people worldwide and is estimated to cause almost 400,000 deaths
annually. Asthma deaths arise primarily during episodes of acute worsening of
symptoms, known as attacks or ‘exacerbations’, which are commonly triggered by
viral upper respiratory infections.
Vitamin D is thought to
protect against such attacks by boosting immune responses to respiratory
viruses and dampening down harmful airway inflammation.
The new study, funded by
the National Institute for Health Research, and published in The Lancet
Respiratory Medicine, collated and analysed the individual data from 955
participants in seven randomised controlled trials, which tested the use of
vitamin D supplements.
Overall, the researchers
found that vitamin D supplementation resulted in:
a 30 per cent reduction in the rate of
asthma attacks requiring treatment with steroid tablets or injections — from
0.43 events per person per year to 0.30.
a 50 per cent reduction in the risk of
experiencing at least one asthma attack requiring Accident and Emergency
Department attendance and/or hospitalisation — from 6 per cent of people
experiencing such an event to 3 per cent.
Vitamin D supplementation
was found to be safe at the doses administered. No instances of excessively
high calcium levels or renal stones were seen, and serious adverse events were
evenly distributed between participants taking vitamin D and those on placebo.
Lead researcher Professor
Adrian Martineau said: “These results add to the ever growing body of
evidence that vitamin D can support immune function as well as bone health. On
average, three people in the UK die from asthma attacks every day. Vitamin D is
safe to take and relatively inexpensive so supplementation represents a
potentially cost-effective strategy to reduce this problem.”
The team’s use of
individual participant data also allowed them to query the extent to which
different groups respond to vitamin D supplementation, in more detail than
In particular, vitamin D
supplementation was found to have a strong and statistically-significant
protective effect in participants who had low vitamin D levels to start with.
These participants saw a 55 per cent reduction in the rate of asthma
exacerbations requiring treatment with steroid tablets or injections — from
0.42 events per person per year to 0.19.
However, due to
relatively small numbers of patients within sub-groups, the researchers caution
that they did not find definitive evidence to show that effects of vitamin D
supplementation differ according to baseline vitamin D status.
Professor Hywel Williams,
Director of the NIHR Health Technology Assessment Programme, said: “The
results of this NIHR-funded study brings together evidence from several other
studies from over the world and is an important contribution to reducing
uncertainties on whether Vitamin D is helpful for asthma — a common condition
that impacts on many thousands of people worldwide.”
Dr David Jolliffe from
QMUL, first author on the paper, added: “Our results are largely based on
data from adults with mild to moderate asthma: children and adults with severe
asthma were relatively under-represented in the dataset, so our findings cannot
necessarily be generalised to these patient groups at this stage. Further
clinical trials are on-going internationally, and we hope to include data from
them in a future analysis to determine whether the promise of today’s results
is confirmed in an even larger and more diverse group of patients.”
1. David A Jolliffe, Lauren
Greenberg, Richard Hooper, Christopher Griffiths, Carlos Camargo Jr, Conor
Kerley, Megan Jensen, David Mauger, Iwona Stelmach, Mitsuyoshi Urashima, Adrian
Martineau. Vitamin D supplementation to prevent asthma exacerbations: systematic
review and meta-analysis of individual participant data’. The Lancet
Respiratory Medicine, 2017 DOI: 10.1016/S2213-2600(17)30346-6