Low Vitamin D Levels Associated With More Asthma Symptoms, Medication Use

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Low Vitamin D Levels Associated With More Asthma Symptoms, Medication Use

_http://healthfreedoms.org/2010/04/19/low-vitamin-d-levels-associated-with-m

ore-asthma-symptoms-medication-use/_

(http://healthfreedoms.org/2010/04/19/low-vitamin-d-levels-associated-with-more-\

asthma-symptoms-medication-use/)

 

 

Low levels of vitamin D are associated with lower lung function and

greater medication use in children with asthma, according to researchers at

National Jewish Health. In a paper published online in the Journal of Allergy &

Clinical Immunology, Daniel Searing, MD, and his colleagues also reported

that vitamin D enhances the activity of corticosteroids, the most effective

controller medication for asthma. “Asthmatic children in our study who had

low levels of vitamin D were more allergic, had poorer lung function and

used more medications,†said Dr. Searing. “Conversely, our findings suggest

that vitamin D supplementation may help reverse steroid resistance in

asthmatic children and reduce the effective dose of steroids needed for our

patients.â€

 

 

The researchers examined electronic medical records of 100 pediatric

asthma patients referred to National Jewish Health. Overall, 47 percent of them

had vitamin D levels considered insufficient, below 30 nanograms per

milliliter of blood (ng/mL). Seventeen percent of the patients had levels below

20 ng/mL, which is considered deficient. These levels were similar to

vitamin D levels found in the general population.

 

 

Patients low in vitamin D generally had higher levels of IgE, a marker of

allergy, and responded positively to more allergens in a skin prick test.

Allergies to the specific indoor allergens, dog and house dust mite, were

higher in patients with low vitamin D levels. Low vitamin D also correlated

with low FEV1, the amount of air a person can exhale in one second, and

lower FEV1/FVC, another measure of lung function. Use of inhaled steroids, oral

steroids and long-acting beta agonists were all higher in patients low in

vitamin D.

 

 

“Our findings suggest two possible explanations,†said senior author

Donald Leung, MD, PhD. “It could be that lower vitamin D levels contribute to

increasing asthma severity, which requires more corticosteroid therapy. Or,

it may be that vitamin D directly affects steroid activity, and that low

levels of vitamin D make the steroids less effective, thus requiring more

medication for the same effect.â€

 

 

The researchers performed a series of laboratory experiments that

indicated vitamin D enhances the action of corticosteroids. They cultured some

immune cells with the corticosteroid dexamethasone alone and others with

vitamin D first, then dexamethasone. The vitamin D significantly increased the

effectiveness of dexamethasone. In one experiment vitamin D and dexamethasone

together were more effective than 10 times as much dexamethasone alone.

 

 

The researchers also incubated immune-system cells for 72 hours with a

staphylococcal toxin to induce corticosteroid resistance. Vitamin D restored

the activity of dexamethasone.

 

 

“Our work suggests that vitamin D enhances the anti-inflammatory function

of corticosteroids,’ said Dr. Leung. “If future studies confirm these

findings vitamin D may help asthma patients achieve better control of their

respiratory symptoms with less medication.â€

 

 

This study comes on the heels of another paper by National Jewish Health

faculty, which showed that low levels of vitamin D in adult asthma patients

are associated with lower lung function and reduced responsiveness to

corticosteroids.

_http://www.medicalnewstoday.com/articles/185816.php_

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