Prenatal Vitamin D Therapy Fails To Prevent Childhood Asthma

Updated results on a study of vitamin D and childhood asthma has concluded that giving extra doses to pregnant women fails to reduce the risk of wheezing and breathing problems in youngsters through age 6 years.

The VDAART study looked at 876 women who were instructed to take a daily prenatal vitamin containing 400 IU of vitamin D beginning at 10 to 18 weeks of pregnancy. Half the women were also asked to take 4,000 IU of the vitamin each day to see if it made a difference in asthma rates. The rest got placebo.

By age 6, 43.5% of the children whose mothers had received the extra vitamin D had asthma or recurrent wheezing, compared to 45.9% in the control group. The difference was not significant, Dr. Augusto Litonjua of Golisano Children's Hospital in Rochester, NY, and colleagues report in The New England Journal of Medicine.

Nor did the risk of asthma or wheezing correlate with maternal 25-hydroxyvitamin D levels during pregnancy.

The research team also found no effect for supplementation in the risk of eczema, allergic rhinitis, or lower-respiratory- tract infections.

All of the women selected for the study were at risk because they, or the biological father of the child, had a history of asthma, eczema or allergic rhinitis.

Previously, 3-year results had found that 24.3% in the treatment group developed asthma or recurrent wheezing vs 30.4% of children whose mothers who didn't get the extra vitamin D, a difference that just missed statistical significance. Those findings were published four years ago in JAMA.

"Although a between-group difference was suggested at early time points through the age of 3 years, this effect was not sustained through the age of 6 years," the researchers write. "Most of the secondary analyses were also null, although there was a small but uncertain effect of prenatal supplementation on total and peripheral airway resistance as measured by impulse oscillometry."

A Danish trial that tested vitamin D supplementation also found it did not prevent asthma through mid-childhood.

—Reuters Staff

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