Major Clinical Trial Reveals Vitamin D Supplements Don't Prevent Bone Fractures in Children

A significant clinical trial by Queen Mary University of London and the Harvard T.H. Chan School of Public Health has produced a surprising result: Vitamin D supplements do not enhance bone strength or reduce the risk of bone fractures in vitamin D-deficient children. This finding, published in Lancet Diabetes & Endocrinology, challenges widespread assumptions about vitamin D's impact on bone health in children.

Childhood fractures, affecting around one-third of children globally before age 18, pose a major health concern. Prior to this study, the potential of vitamin D supplements to improve bone strength and prevent fractures had garnered increasing interest. However, no clinical trials had tested this hypothesis in children until now.

The research team, including Dr. Ganmaa Davaasambuu from Harvard and Professor Adrian Martineau from Queen Mary University, conducted the largest randomized controlled trial on vitamin D supplementation in children. The study involved 8,851 Mongolian schoolchildren aged 6-13, a population with a high fracture burden and prevalent vitamin D deficiency. Over three years, these children received a weekly oral dose of vitamin D. While supplementation effectively normalized vitamin D levels in 95.5% of participants, it surprisingly showed no effect on reducing fracture risk or improving bone strength, as measured in 1,438 children using quantitative ultrasound.

The trial's findings necessitate a reevaluation of vitamin D supplements' role in pediatric bone health. Dr. Davaasambuu notes the striking absence of any fracture risk reduction or bone strength enhancement, suggesting that concurrent calcium supplementation might be necessary for effectiveness, a factor not included in this study.

Professor Martineau highlights an important caveat: children with rickets were excluded from the trial for ethical reasons. Therefore, the study's conclusions apply only to vitamin D-deficient children without developed bone complications. He stresses the continued importance of adequate vitamin D intake for rickets prevention, in line with UK government guidance recommending a daily intake of 400 IU vitamin D.

This groundbreaking study shifts the understanding of vitamin D's role in pediatric bone health, signaling a need for revised strategies in addressing childhood bone fractures and deficiencies.