Maternal vitamin D and growth of under-five children: a systematic review and meta-analysis of observational and interventional studies

ABSTRACT

Background

Even though previous systematic reviews have reported on the role of prenatal vitamin D on birth outcomes, its effect on child growth is poorly understood.

Objective

To synthesize a systematic summary of the literature on the effect of maternal vitamin D supplementation on the linear growth of under-five children.

Method

This study includes studies (both observational and interventional with a control group) that evaluated the effects of prenatal vitamin D status on child linear growth. The mean child length/length for age with 95% confidence interval (CI) was pooled as the weighted mean difference using a random-effects model. A funnel plot was used to assess potential publication bias.

Results

A total of 45 studies and 66 reports covering a total population of 44,992 (19,683 intervention or high vitamin D group, and 25,309 control or low vitamin D group) were analyzed. Studies spanned from 1977 to 2022. The pooled weighted mean difference was 0.4 cm (95% CI: 0.15–0.65). A subgroup analysis, based on vitamin D supplementation frequency, showed that mothers who supplemented monthly or less frequently had a 0.7 cm (95% CI: 0.2–1.16 cm) longer child. Supplementation with a dose of >2000 international units increased child length at birth. The weighted mean difference was 0.35 cm (95% CI: 0.11–0.58).

Conclusion

The evidence from this review shows that maternal supplementation of vitamin D is associated with increased birth length. This is apparent at higher doses, low frequency (monthly or less frequent), and during the second/third trimester. It appears that vitamin D supplementation during pregnancy is protective of future growth in under-five children. Clinical trials are needed to establish evidence of effectiveness for the frequency and dose of supplementation.

KEYWORDS:

• Growth
• maternal
• vitamin D
• children
• length

Responsible Editor

Jennifer Stewart Williams

Responsible Editor

Jennifer Stewart Williams

Acknowledgments

TAZ’s time was covered by a fellowship funded by the TRAIN@Ed Marie Skłodowska-Curie Actions program.

Disclosure statement

None of the authors have any competing interest.

Ethics and consent

Not applicable.

Paper context

Prenatal intake of vitamin D has positive effects on birth outcomes. Vitamin D supplementation during pregnancy is associated with higher birth length and the effects are more evident at higher doses, low frequency, and in later stages of pregnancy. Consistent and adequate vitamin D levels are crucial in pregnancy. Future clinical trials are needed to evaluate frequency, dose, and adherence.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/16549716.2022.2102712.

Additional information

Funding

The author(s) reported that there is no funding associated with the work featured in this article.

Notes on contributors

Addis Alem

AAT conceived the study and drafted the manuscript. All authors contributed substantially to the methodology, analysis, and interpretation of data. All authors read and approved the final version of the manuscript. AAT will be responsible for the accuracy or integrity of any part of the work.