Researchers from Trinity College Dublin have developed a novel set of tools for designing vitamin D clinical trials that capture large seasonal and population-wide differences in vitamin D status, typically seen in individuals. Their study published in the journal Scientific Reports (today, Monday 31st May 2021) provides a framework for clinical trials to establish whether vitamin D supplementation is effective against a given disease.
The study also reveals that many trials which failed to find any association between vitamin D and disease prevention may have been underpowered or conducted without enough subjects to detect a benefit of vitamin D.
You can read the full journal paper here: https://go.nature.com/3uERjgO
The problem:
Study synopsis
Dr Jason Wyse, Assistant Professor in Statistics at Trinity College and a senior author on the study, said:
"Vitamin D levels in our blood have an annual rhythm, keeping time with the seasons of the year. Our tools allow researchers to take account of these important characteristics when planning a trial, modelling vitamin D benefit at the individual micro-level and bringing these together to get a view of what would happen at the macro-level of a trial."
Dr Lina Zgaga, Associate Professor in Epidemiology at Trinity College and a senior author on the study, said:
"We simulated a wide range of scenarios and approximated how many participants we would need, given the range of starting points, to have sufficient statistical power to detect an effect. We found that once we take seasonal and population differences into account, we would need a larger number of participants than traditional approaches would suggest. The signal - a treatment benefit of Vitamin D - may have been lost to noise in many trials.
We now have new understanding about the factors that might have interfered with our ability to detect benefit in vitamin D trials. Going forward, we need appropriately designed and adequately powered vitamin D trials, and we hope this new tool will help researchers to ensure this. While we await these trials, I would encourage everyone to take vitamin D supplements."
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You can read the full journal manuscript here: Power determination in vitamin D randomised control trials and characterising factors affecting it through a novel simulation-based tool | Scientific Reports (nature.com)
Scientific Reports