Background Vitamin D supplements are widely used for improving bone health in children
and adolescents, but their effects in vitamin D–deficient children are unclear. Objectives This
study aimed to examine whether the effect of vitamin D supplementation on bone mineral
density (BMD) in children and adolescents differs by baseline vitamin D status and estimate
the effect in vitamin D–deficient individuals. Methods This is a systematic review and
individual participant data (IPD) meta-analysis. We searched the Cochrane Central Register …