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High doses of prenatal vitamin D not associated with children’s asthma risk

Women who took high doses of vitamin D supplementation during pregnancy did not impact their child’s risk for asthma by the age of 6 years, according to data recently published in JAMA.

“The Copenhagen Prospective Studies on Asthma in Childhood 2010 vitamin D randomized clinical trial found that at the age of 3 years, children of women randomized to high-dose vs. standard-dose vitamin D did not have a statistically significant reduced risk of persistent wheeze; however, a clinically important protective effect could not be excluded,” Niklas Brustad, MD, of the Copenhagen Prospective Studies on Asthma in Childhood, in Copenhagen, Denmark, and colleagues wrote.

“Because diagnosing asthma early in life is difficult, we followed up the children at the age of 6 years to assess the risk of current asthma,” they added.

Researchers analyzed data from 545 children in the earlier Denmark-based trial. Approximately half of these children’s mothers had taken high doses of vitamin D while pregnant, and the remainder had taken standard doses of vitamin D.

Brustad and colleagues found that 23 of the 274 children in the high-dose group and 18 of 268 children in the standard group developed asthma by age 6 (OR = 1.27; 95% CI, 0.67-2.42). The yearly prevalence of persistent asthma or wheeze through the age of 6 years, lung function outcomes, bronchial reactivity, fractional exhaled nitric oxide concentration, allergic sensitization or rhinitis were all also not significantly impacted by the vitamin D dose.

“Future studies should investigate whether the effect of prenatal vitamin D supplementation is modified by environmental, dietary or genetic factors,” Brustad and colleagues concluded. – by Janel Miller

Disclosures: Brustad reports no relevant financial disclosures. Please see the research letter for all other authors’ relevant financial disclosures.