Higher-than-standard vitamin D not beneficial for child neurodevelopment: JAMA

Vitamin D may be important for neurodevelopment. The optimal daily dose of vitamin D for early brain development is not known.

A group of researchers from Finland conducted a study to test whether a higher (1200 IU) vs standard (400 IU) dose of vitamin D3 has beneficial effects on neurodevelopment in the first 2 years of life and whether serum 25-hydroxyvitamin D concentration is associated with neurodevelopment.

This double-blind, interventional randomized clinical trial involved healthy infants born full-term between January 1, 2013, and June 30, 2014, at a maternity hospital in Helsinki, Finland, at the 60th northern latitude. Two-year follow-up was conducted by May 30, 2016. Data analysis was by the intention-to-treat principle. Data were analyzed from November 1, 2020, to May 31, 2021.

The results of the study are as follows:

· Of the 987 families recruited, 495 children were randomly assigned to receive 400 IU of vitamin D3, and 492 children were randomly assigned to receive 1200 IU of vitamin D3.

· A total of 801 families participated in the follow-up at 12 and/or 24 months, with 404 children in the 400-IU group and 397 children in the 1200-IU group.

· All children were of Northern European ethnicity. No differences were found between the 400-IU group and the 1200-IU group in the mean (SD) adjusted Ages and Stages Questionnaire total score at 12 months or 24 months.

· No differences were found between the 400-IU group and the 1200-IU group at 24 months in the mean (SD) adjusted Infant-Toddler Social and Emotional Assessment externalizing domain score, internalizing domain score, dysregulation domain score, or competencies score.

· The 1200-IU group did have a higher risk in the adjusted model of scoring 1.5 SDs or more on the externalizing domain score.

· Levels of serum 25-hydroxyvitamin D were not associated with the primary outcomes.

The researchers concluded that higher-than-standard vitamin D3 doses provide no systematic benefits for child neurodevelopment up to 2 years of age. However, the potential disadvantageous effects of higher doses could not be fully excluded; even if minimal, the potential nonbeneficial effects of higher-than-standard doses warrant further studies in which both safety and benefits should be evaluated.

Reference:

Effect of High-Dose vs Standard-Dose Vitamin D Supplementation on Neurodevelopment of Healthy Term Infants: A Randomized Clinical Trial.