The influence of maternal vitamin D supplementation on infant vitamin D status: A systematic review and meta-analyses

Background: Inconsistencies exist with regard to effect of maternal vitamin D supplementation on infant vitamin D status. The inconsistencies could be attributed to numerous factors, such as duration of intervention and dosage, among others. In this work, we conducted a systematic review and meta-analysis to determine the influence of maternal vitamin D supplementation on infant vitamin D status. Methods: A comprehensive systematic search was performed in Scopus, EMBASE, Web of Science, and PubMed/ MEDLINE, by investigators, from database inception until November 2019, without using any restrictions. Weighted mean difference (WMD) with the 95 % CI was used for assessing the effects of maternal vitamin D supplementation on 25(OH) D levels in infants. Results: Overall results from 14 studies revealed a non-significant effect of maternal vitamin D administration on the level of 25(OH) D in breastfeeding infants (WMD: -0.464 ng/mL, 95 % CI: -6.68 to 5.75, p = 0.884, I-2 = 98 %). Subgroup analyses demonstrated that vitamin D supplementation dosage >= 2000 IU/day (WMD: 9 ng/mL, 95 % CI: 8.19, 9.82, I-2 = 99 %) and intervention duration >= 20 weeks (WMD: 16.20 ng/mL, 95 % CI: 14.89, 17.50, I-2 = 99 %) significantly increased 25(OH) D. Conclusions: The main results indicate a non-significant increase in infant vitamin D following maternal vitamin D supplementation. Additionally, vitamin D supplementation dosage >= 2000 IU/day and intervention duration >= 20 weeks significantly increased infant 25(OH) D.