High-dose vitamin D in pregnancy fails to prevent wheezing risk in children

These are sobering findings. Even if we assume that prenatal vitamin D supplementation will prove more protective as the children in these studies grow older, vitamin D insufficiency still would explain only a small portion of the current asthma epidemic.

But neither study showed any unwanted effects from supplementation, so it seems reasonable for clinicians to prescribe vitamin D to mothers at high risk of having children with asthma by virtue of their own asthma, eczema, or allergic rhinitis – especially if those mothers are deficient in vitamin D. However, the data in these two clinical trials do not support the use of very high-dose vitamin D, since any beneficial effects achieved with 4,400 IU/day were identical to those achieved with approximately half as high a dose.

Dr. Erika von Mutius is at Ludwig Maximilians University, Munich. Dr. Fernando D. Martinez is at the asthma and airway disease research center and the department of pediatrics at the University of Arizona, Tucson. Both reported having no relevant financial disclosures. Their remarks are adapted from an editorial accompanying the two reports (JAMA 2016;315[4]:347-8.).