Vitamin D supplementation does not reduce the risk for asthma exacerbation in children overall, but does reduce the risk in those with low serum 25-hydroxyvitamin D (25[OH]D) concentrations, according to a review recently published in Nutrients.

Qinyuan Li, M.D., from the Chongqing Key Laboratory of Pediatrics in China, and colleagues conducted a systematic review and meta-analysis to examine the effects of vitamin D supplementation in children with allergic diseases. Data were included from 32 randomized controlled trials (RCTs) comparing vitamin D supplementation with placebo among 2,347 children.

The researchers found that compared with placebo, vitamin D supplementation did not reduce the risk for asthma exacerbations overall (risk ratio, 0.84; 95 percent confidence interval, 0.65 to 1.08; P = 0.18), but there was a reduction observed in the risk for asthma exacerbation for children with baseline serum 25(OH)D <10 ng/mL (risk ratio, 0.48; 95 percent confidence interval, 0.28 to 0.83; P = 0.009). A significant reduction was seen in the Scoring Atopic Dermatitis or the Eczema Area and Severity Index scores in children with atopic dermatitis with vitamin D versus placebo (standardized mean difference, −0.5; 95 percent confidence interval, −0.87 to −0.12; P = 0.009). For children with allergic rhinitis, vitamin D supplementation reduced the symptom-medication score compared with placebo (mean, 43.7 versus 57.8).

"Large-scale and well-designed RCTs are needed to confirm these conclusions and investigate the optimum regimen of vitamin D and the patients who would benefit most from vitamin D supplementation," the authors write.

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