Vitamin D insufficiency, usually defined by serum 25-hydroxyvitamin D (25(OH)D) levels < 50 nmol/L is highly prevalent in the general population although supplementation with vitamin D3 got more and more common in recent years. Clinical trials showed that vitamin D3 supplementation can prevent cases of acute respiratory tract infections and cancer mortality while being safe with no more adverse events than a placebo. Evidence from trials regarding the efficacy for reducing inflammatory biomarkers and reducing low back pain is inconclusive. The efficacy of vitamin D3 supplementation with respiratory tract infections suggests that vitamin D3 supplementation may also help to prevent covid-19 infections and associated deaths.
It is of interest how the safety and efficacy data of vitamin D3 supplementation obtained from well-defined clinical trial populations translate into the safety and effectiveness in the real world. Therefore, the UK Biobank study is the ideal data source to address the following research aims:
To address the associations of vitamin D3 supplementation and vitamin D insufficiency with back pain, infections, all-cause and cause-specific mortality, surrogate parameters for inflammation and acute infections. A special focus will be put on covid-19 positive infections and deaths. In addition, we will also look into the safety of vitamin D3 supplementation, which can lead to increased serum calcium levels and subsequently to kidney stones.
All research questions shall be answered within 3 years but the project on covid-19 infections will be prioritized to give answers within a few months after data access has been granted. If vitamin D insufficiency is associated with any covid-19 related health outcome, vitamin D supplementation for high-risk groups could be recommended. Vitamin D insufficiency is common in these groups, but could be rapidly and safely eliminated at very low cost.