Ganmaa et al. Influence of vitamin D supplementation on muscle strength and exercise capacity in Mongolian schoolchildren: secondary outcomes from a randomised controlled trial: BMJ Open Sport & Exercise Medicine 2024;10:e002018.
Middelkoop et al. Influence of vitamin D supplementation on muscle strength and exercise capacity in South African schoolchildren: secondary outcomes from a randomised controlled trial (ViDiKids): BMJ Open Sport & Exercise Medicine 2024;10:e002019.
The full articles can be found here and here.
Tell us more about yourself and the author team.
We are a team of doctors and clinical trialists from the UK, South Africa, and Mongolia studying vitamin D’s effects on children’s health.
What is the story behind your study?
Vitamin D has long been important for calcium homeostasis and musculoskeletal health, and several observational studies have reported associations between lower vitamin D status and reduced exercise tolerance / physical fitness. However, large clinical trials have been lacking in testing for a cause-effect relationship.
In your own words, what did you find?
We did two placebo-controlled weekly vitamin D supplementation trials in primary schoolchildren, administered for 3 years – one in Cape Town, South Africa, the other in Ulaanbaatar, Mongolia. In both studies, the trial supplements effectively boosted serum 25-hydroxyvitamin D concentrations of children randomly selected to receive them. However, this improvement in vitamin D status was not associated with any improvement in outcomes studied, including exercise tolerance (20m shuttle runs), grip strength and explosive leg power (measured using standing long jump).
What was the main challenge you faced in your study?
Maintaining adherence to study medication for 3 years was a potential challenge, but we achieved this by directly observing supplement administration at participating schools.
If there is one take-home message from your study, what would that be?
Weekly vitamin D supplementation effectively improved the vitamin D status of schoolchildren in South Africa and Mongolia, but this did not result in improved exercise tolerance or muscle strength.