Vitamin D Levels Linked to Asthma Meds

[Guest guest]

Vitamin D may boost the anti-inflammatory efficacy of asthma medications

but tends to be low in kids who need the drugs, researchers said.

Children taking oral or inhaled corticosteroids appeared to have lower

vitamin D levels in a dose-related manner (*P*=0.001), A. Searing,

MD, of National Jewish Health in Denver, and colleagues found.

In vitro experiments by the group showed that vitamin D improved

anti-inflammatory markers MKP-1 and interleukin (IL)-10 and enhanced the

activity of dexamethasone (Decadron, Dexpak) more than 10-fold.

" The implication is vitamin D could have a steroid-sparing effect in

asthma, " Searing said in an interview here at the American Academy of

Allergy, Asthma, and Immunology meeting where he presented the results.

However, whether vitamin D supplementation would translate to lower steroid

doses or better asthma control remains to be seen, he cautioned.

Moreover, the researchers cautioned that the study could only suggest a

correlation, not causality.

If there was causality involved, it's not clear which direction, Searing

said -- whether steroid medications or simply more severe asthma reduced

vitamin D levels in some way or whether low vitamin D might have caused more

severe symptoms that necessitated treatment.

Nevertheless, treating vitamin D insufficiency may make sense given its

links to a wide range of ill effects on health and the vitamin's important

role in bone health, Searing said.

At his institution, " we tend to supplement patients if they are under 30

ng/mL, " he told *MedPage Today*.

Vitamin D insufficiency rates affect an estimated 20%

<http://www.medpagetoday.com/Pediatrics/GeneralPediatrics/16625>to

70%<http://www.medpagetoday.com/Pediatrics/GeneralPediatrics/15359>of

American children, depending on the level at which insufficiency is

defined.

In Searing's retrospective study, 47% of the 99 pediatric asthma patients

seen at National Jewish Health had vitamin D levels below 30 ng/mL,

considered insufficient.

Although this was similar to the prevalence in the overall pediatric

population, lower vitamin D levels in the asthmatic children were associated

with higher immunoglobulin E levels (*P*=0.01) and poorer lung

function (*P*=0.33

to *P*=0.004).

Median vitamin D levels associated with medication use were significantly

lower for children on:

- Inhaled corticosteroids (29 versus 35 ng/mL, *P*=0.0475)

- Oral corticosteroids (25 versus 32 ng/mL, *P*=0.02)

- Long-acting beta agonists (25 versus 34 ng/mL, *P*=0.0007)

- Higher total steroid doses (*P*=0.001 for trend)

When peripheral blood mononuclear cells from 11 of the children and four

healthy controls were cultured, vitamin D significantly increased the levels

of the anti-inflammatory marker MKP-1 (*P*<0.01 to *P*<0.001) and the

anti-inflammatory cytokine IL-10 (*P*<0.05) with greater effects at a higher

vitamin D dose.

" Whether or not that would correlate physiologically really cannot be

inferred from our data, " Searing warned in an interview**.

But, he speculated, low vitamin D may have greater implications for the

health of children with asthma than those who don't have it.

*Primary source: *American Academy of Allergy, Asthma, and Immunology

Source reference:

Searing DA, et al " Vitamin D Levels in Children with Asthma, Atopic

Dermatitis, and Food Allergy " *AAAAI* 2010; Abstract 176.

http://www.medpagetoday.com/MeetingCoverage/AAAAI/18720

--

Ortiz, MS, RD

Registered Dietitian Day is Wednesday, March 10, 2010

" Nutrition is a Science, Not an Opinion Survey "