A study showing relationship between poor lung functions and ineffective response to asthma treatment with Vitamin D deficiency.
July 13, 2012 — When using inhaled corticosteroids to treat patients
with persistent asthma, vitamin D levels should be closely monitored and
supplemented, if necessary, according to results from a multicenter
placebo-controlled study of 1041 children with mild to moderate
persistent asthma. Ann Chen, MD, MPH, assistant professor in the
Department of Population Medicine at Harvard Medical School and Harvard
Pilgrim Health Care Institute, Boston, Massachusetts, and colleagues
found that children with asthma who are deficient in vitamin D show less
improvement over the course of a year's therapy with corticosteroids
than do children who have more normal levels.
"In asthmatic children treated with inhaled corticosteroids, vitamin D
deficiency is associated with poorer lung function than [in] children
with vitamin D insufficiency or sufficiency," the authors write.
The findings were published online July 13 in the American Journal of Respiratory and Critical Care Medicine.
Dr. Chen and colleagues note that the prevalence of both asthma and
vitamin D deficiency have increased in recent years, suggesting there
may be a causal link between the 2. "Multiple studies have supported the
hypothesis that asthma and vitamin D deficiency are related," they
write, "but few studies have examined the direct effects of vitamin D
levels and corticosteroid treatment on lung function in children with
To look more closely into that possible association, the
investigators analyzed data from the Childhood Asthma Management
Program, a multicenter trial of 1041 children diagnosed with mild to
moderate persistent asthma. All the children were between 5 and 12 years
On the children's entry into the study, administrators measured
levels of 25-hydroxyvitamin D in their serum and then randomly assigned
them to receive 1 of 3 agents: the inhaled corticosteroid budesonide,
the nonsteroidal anti-inflammatory agent nedocromil, or placebo. Data
regarding baseline vitamin D levels were available for 1024 children.
Spirometry readings were obtained before and after the children used
their inhalers. Those tests were conducted at intake into the study and
again after a year of therapy.
The investigators also categorized the children into 3 groups
according to their serum levels of vitamin D: those who had sufficient
levels (>30 ng/mL), those deemed to have insufficient levels (20 - 30
ng/mL), and those with deficient levels (<20 ng/mL).
Main outcome measures were changes in prebronchodilator forced expiratory volume in 1 second (FEV1), bronchodilator response, and provocative concentration of methacholine producing a 20% decline in FEV1.
The researchers report that of the 1024 children, 663 (nearly 65%)
had sufficient levels of vitamin D, 260 (just over 25%) had insufficient
levels, and 101 (roughly 10%) had deficient levels.
Compared with children who had sufficient or insufficient levels of
vitamin D, those with deficient levels were more likely to be older and
black and to have a higher body mass index, the researchers write.
Among children being treated with corticosteroids, those who were
vitamin D deficient were less likely than other children taking the same
drug to show big improvements in prebronchodilator FEV1 scores after 12 months of treatment.
More specifically, children with insufficient levels of vitamin D
showed a 330-mL increase, those with sufficient levels showed a 290-mL
increase, and children with vitamin D deficiencies had only a 140-mL
increase in prebronchodilator FEV1. That difference was significant to a P
value of < .007, after adjustments for age, sex, race, body mass
index, number of visits to emergency departments, and the season of the
year that serum for the vitamin D specimen had been drawn.
The investigators do acknowledge a couple of limitations of the
study; namely, that the sample size of children with vitamin D
deficiencies was relatively small (101 children) and that vitamin D
levels were assessed only once, on entry into the trial.
Even so, Dr. Wu and colleagues say the present study is the first to
suggest that vitamin D sufficiency in patients treated with inhaled
corticosteroids is associated with improved lung function in patients
with mild to moderate persistent asthma. They suggest monitoring vitamin
D levels and, if they are found to be low, considering supplementation.
This study was funded by the National Heart,
Lung, and Blood Institute, the Childhood Asthma Management Program, and
the National Center for Research Resources. The authors have disclosed
no relevant financial relationships.
Am J Respir Crit Care Med. Published online July 13, 2012.
Original Article from medscape: here