 Vitamin D is essential for bone and muscle health, and its adequacy during childhood is critical for normal skeletal development. In a study conducted in Ireland, researchers found that 23% of children were vitamin D deficient with the highest rates occurring in disadvantaged areas and among older children. Female gender and winter season were also associated with increased risk of vitamin D deficiency. To address this issue, public health strategies such as food fortification should be considered. This article was authored by Helena Scully, Amon Laird, Martin Healy, and others.