Adding an oral vitamin D supplement to regular intranasal corticosteroid dosing can improve symptoms of seasonal allergic rhinitis beyond that seen with corticosteroids alone in patients who are not vitamin D deficient, according to study results presented here at the American Academy of Allergy, Asthma and Immunology 2012 Annual Meeting.
The findings add to a number of reports at the meeting suggesting that vitamin D supplementation might be beneficial in patients with allergies.
"Vitamin D has been shown to play a role in innate immunity and the generation of antimicrobial peptides. It also has a number of immunological effects on T cells, dendritic cells, and macrophages," said James Lane, BA, a researcher at the University of Chicago, Illinois, who presented the findings.
These findings must be viewed with caution, said lead investigator Fuad Baroody, MD, a pediatric head and neck surgeon at the University of Chicago. "This was a small study, a pilot study. More work needs to be done before people can run out and add vitamin D to intranasal steroids," he said in an interview with Medscape Medical News.
In the double-blind placebo-controlled study, patients 18 to 45 years of age with seasonal allergic rhinitis received fluticasone propionate 200 µg/day, and were randomized to receive either vitamin D 4000 IU/day for 2 weeks (n = 17) or placebo (n = 18).
Subjects had at least a 2-year history of seasonal allergic rhinitis and a positive skin test to tree, grass, and/or ragweed.
At baseline, serum 25-hydroxy-vitamin D levels were within the normal range and similar in the vitamin D and placebo groups (29.6 vs 29.4 ng/dL). After 2 weeks, levels in the vitamin D group rose significantly from baseline to 37.2 ng/dL (P = .001); in the placebo group, there was no rise.
"There's variation on what people consider appropriate levels of vitamin D," explained Dr. Baroody. "Most recommendations are for levels around 30 or so. These were not vitamin-deficient people, but we bumped it up a little bit to within a still reasonable range, and nobody had side effects from having too much vitamin D."
According to daily self-rated nasal symptoms, including sneezing, nasal congestion, and drip, subjects in both groups noted significant daytime improvements from baseline.
However, subjects in the vitamin D group noted a decreased symptom score of 6.9 points from baseline, which was statistically significant and superior to the 3.7 point drop in the placebo group (P = .04).
"Just giving vitamin D on top created a significant drop — almost a 50% drop," said Dr. Baroody. "The magnitude is impressive, actually. If that is duplicated in a big trial, it would be pretty spectacular."
Nighttime symptoms were not presented at the meeting, but Dr. Baroody said they were "not as spectacular." As a result, the reduction in 24-hour symptom relief was not statistically different between the vitamin D and placebo groups (11.3 vs 7.6 points; P = .09).
Similarly, although there was a statistically significant improvement from baseline in quality of life in both groups (P= .0028), there was no significant difference between the vitamin D and placebo groups (2.5 vs 2.0 points).
"A change of 0.5 is considered to be clinically meaningful, and both groups had improvements well beyond that," said Lane.
In response to a comment from the audience, Dr. Baroody acknowledged that perhaps the real strength of vitamin D supplementation in this group was not in better, but rather in faster, symptom control; all measures showed patients in the vitamin D group responding within 2 days and sustaining their response level.
"That's an interesting way of looking at it. I will examine that in more detail," he said.
"I think people don't really know what the vitamin D story is," Rachel Miller, MD, associate professor of medicine in pediatrics and environmental health sciences at Columbia University Medical Center in New York City, toldMedscape Medical News.
"My bias is to do a randomized trial and see what vitamin D supplementation does, because most of the work so far has been observational. I know people are already doing it, but I personally look forward to more evidence from randomized trials."
The study received no funding from industry. Mr. Lane and Dr. Miller have disclosed no relevant financial relationships. Dr. Baroody reports being on the speaker's bureau for Merck and GlaxoSmithKline.
American Academy of Allergy, Asthma and Immunology (AAAAI) 2012 Annual Meeting: Abstract 510. Presented March 4, 2012.