Methods
Within the UK Maternal Vitamin D Osteoporosis Study (MAVIDOS) double-blind, randomised, placebo-controlled trial, we examined the relation of maternal vitamin D supplementation during pregnancy with offspring atopic eczema at ages 12, 24 and 48 months. In MAVIDOS, pregnant women were allocated to either cholecalciferol 1000 IU/day or matched placebo, taken from around 14 weeks’ gestation until delivery, with the primary outcome of neonatal whole-body bone mineral content. The prevalence of atopic eczema in the offspring was ascertained at ages 12 (n=636), 24 (n=611) and 48 (n=450) months, based on the UK Working Party Criteria for the Definition of Atopic Dermatitis.