New findings from a multinational collaboration show that vitamin D supplements did not improve bone strength or lower fracture risk in children with deficiency. The research, conducted by scientists from Queen Mary University of London in partnership with the Harvard School of Public Health, was reported in a study published in Lancet Diabetes & Endocrinology.
In the trial, more than 8,000 schoolchildren aged 6 to 13 from Mongolia, a region known for high fracture rates and common vitamin D deficiency, were asked to take vitamin D supplements for a three-year period. At the study’s outset, it was documented that a striking 95.5 percent of the participants were deficient in vitamin D, underscoring the scale of the issue in this population.
By the end of the intervention, researchers updated health data and assessed bone strength using ultrasound technology. The results showed that vitamin D supplementation did not yield improvements in bone strength for children and adolescents, nor did it reduce the likelihood of fractures. Notably, during the three-year trial, the deficiency in vitamin D was corrected among participants, yet this improvement did not translate into the expected protective effect on bone health.
The investigators propose that the absence of observed benefits may be linked to the absence of concurrent calcium supplementation. In other words, vitamin D alone did not produce the hoped-for bone health advantages, suggesting that a combined approach might be necessary to influence bone outcomes effectively in vitamin D–deficient populations.
During the screening process, children found to have rickets were excluded from participating because administering a placebo in such cases would be unethical. Consequently, the study’s conclusions apply specifically to children who had low vitamin D levels without clinical complications at the outset of the trial. This delimitation is important for interpreting the applicability of the findings to broader pediatric groups.
There is a broader caution drawn from the study in relation to nutrient supplementation. While vitamin D is essential for bone health, this trial emphasizes that supplementation without attention to other minerals, particularly calcium, may not yield the desired skeletal benefits. The results contribute to a growing body of evidence that nutrient interdependencies matter when addressing bone health in children, especially in settings with prevalent deficiencies. Researchers and public health planners may consider these data when designing interventions for pediatric bone health, weighing the potential benefits of combined nutrient strategies against the risks and costs of widespread supplement use. The study’s authors and collaborating institutions highlight the value of continuing to examine how nutrient interactions influence bone development in diverse populations, and they call for further research to identify which combinations of nutrients most effectively support skeletal strength in vitamin D–deficient children.
These findings remind clinicians, policymakers, and families that correcting a single nutrient deficiency does not automatically guarantee improved bone outcomes. The study invites a broader discussion about comprehensive nutritional strategies for children living in regions with limited sunlight exposure and dietary gaps. It also underscores the importance of context when evaluating the impact of supplements on growth and development across different populations, and it supports ongoing monitoring and evaluation of public health interventions aimed at reducing fracture risk among youth.