Prenatal high-dose vitamin D not linked to asthma at age 6

(HealthDay)—High-dose vitamin D supplementation in pregnancy is not associated with a child's risk for asthma at age 6 years, according to a research letter published in the March 12 issue of the Journal of the American Medical Association.

Nicklas Brustad, M.D., from Herlev and Gentofte University Hospital in Copenhagen, Denmark, and colleagues followed children from the Copenhagen Prospective Studies on Asthma in Childhood 2010 vitamin D randomized clinical trial to age 6 years to assess the risk for current asthma. Women were randomly assigned to receive 2,400 IU/day vitamin D or placebo in addition to the recommended intake of 400 IU/day during week 24 of pregnancy. A total of 581 children were analyzed at age 3 years; 545 of these children were available for analysis at age 6 years.

The researchers found that asthma was diagnosed in 8 and 7 percent of children in the high-dose vitamin D and placebo groups, respectively (odds ratio, 1.27 [95 percent confidence interval, 0.67 to 2.42; P = 0.46]; adjusted odds ratio, 1.21 [95 percent confidence interval, 0.63 to 2.32; P = 0.57]). No effect of the supplementation was seen in an analysis of the yearly prevalence of persistent wheeze or asthma through age 6 years (odds ratio, 0.87; 95 percent confidence interval, 0.59 to 1.28; P = 0.48).

"Future studies should investigate whether the effect of prenatal vitamin D supplementation is modified by environmental, dietary, or genetic factors," the authors write.

One author disclosed financial ties to the pharmaceutical industry.