P128 the risk of atopic eczema in breastfed offspring whose mothers were supplemented with vitamin D during pregnancy

Abstract Atopic dermatitis (AD) is a chronic inflammatory skin condition affecting up to 22.5% of children globally and associated with significant morbidity. The prevalence of vitamin D deficiency has been previously observed in children with AD, with several studies reporting that vitamin D supplementation lessens disease severity. Studies assessing the effect of maternal vitamin D supplementation on the risk of offspring AD have shown conflicting results. The aim of this systematic review was to investigate the effect of vitamin D supplementation during pregnancy on the development of AD in offspring. We systematically reviewed MEDLINE, Embase, the Cochrane Library, Scopus, and Web of Science from their inceptions to 11 June 2023. Included studies clearly documented the dose of vitamin D supplementation administered either preconception or during pregnancy, the duration of breastfeeding, a gestational age at birth of ≥ 35 weeks, and the assessment of AD within the first 3 years of life. Systematic reviews, case reports and letters to the editor were excluded. GRADE and risk-of-bias assessments were performed for all included studies and their primary outcomes. The primary outcome was the rate of offspring AD within 3 years in breastfed infants. A systematic search identified 248 citations, with 6 studies meeting the inclusion criteria. Vitamin D supplementation doses ranged from 248 IU to 200 000 IU. Breastfeeding duration, documented in all studies, was adjusted for in analyses. The meta-analysis of the six studies comparing maternal vitamin D supplementation to placebo reported an odds ratio of 0.85 (95% confidence interval 0.70–1.04) for offspring AD. Season of birth emerged as a potential factor for AD, with two high-quality studies suggesting a nonsignificant association. Maternal body mass index and fat mass showed no effect on the risk of offspring AD at 12 months. In conclusion, this systematic review found that maternal vitamin D supplementation resulted in a slight nonsignificant reduction in the risk of infantile eczema in breastfed infants. The findings challenge claims of maternal vitamin D supplementation in the prevention of offspring AD. This underscores the need for further high-quality evidence focusing on this topic.