746 - Vitamin D supplementation and acute respiratory infection healthcare visits in early childhood: a systematic review and meta-analysis

Publication Number: 746.7021

Marisa van Arragon, University of Auckland, Auckland, Auckland, New Zealand; Cameron C. Grant, University of Auckland, Auckland, Auckland, New Zealand; Robert K. Scragg, School of Population Health, University of Auckland, Auckland, Auckland, New Zealand; Vanessa Jordan, University Of Auckland, Auckland, Auckland, New Zealand

Background: Systematic reviews of vitamin D supplementation have reported that vitamin D supplementation prevents acute respiratory infections (ARIs) in children. Whether vitamin D supplementation prevents ARI healthcare visits in early childhood has not been systematically reviewed.

Objective: To conduct a Cochrane Systematic Review to determine if vitamin D supplementation during pregnancy and early childhood prevents ARI healthcare visits.

Design/Methods: The protocol for this review has been published (DOI: 10.1002/14651858.CD015111). We searched CENTRAL, PubMed, Embase, CINAHL, EBSCO, Web of Science, Global Index Medicus, Register of Controlled Trials platforms and sources of unpublished data from inception to July 2023. Included randomized controlled trials (RCTs) compared vitamin D to placebo or higher dose (≥1000 IU) versus lower dose (≤1000 IU) vitamin D supplementation, given from early pregnancy up to age 5 years. We included all trial author-defined healthcare visits, which may include a primary or secondary healthcare visit, or both, or a parental report of a healthcare visit made for an ARI.

Results: From 5434 records screened, we included 107 studies (n=31,521). Twelve (n=3829) studies reported healthcare data. Ten studies compared vitamin D versus placebo and two studies compared higher versus lower dose vitamin D. The types of ARI and healthcare visits measured differed between every study.
In the vitamin D versus placebo studies, the proportion of children making ARI healthcare visits was smaller in the vitamin D group (Risk Ratio (RR)=0.95 [95% Confidence Interval (CI) 0.91-1.00]; ten studies, n=2447, I²=59%).
In the higher versus lower dose studies the proportion of children making ARI healthcare visits did not differ (RR=0.94 [95% CI 0.81-1.10]; two studies, n=1382, I²=0%).

Conclusion(s): In comparison to placebo, vitamin D supplementation during pregnancy and early childhood prevents early childhood ARI healthcare visits. Higher versus lower vitamin D dosage did not appear to alter the risk of early childhood ARI healthcare visits. Acute respiratory infections and healthcare visits were measured differently in each included study indicating a need for standardisation in research methods in future trials.