Regular sunscreen application reduces the risk of skin cancer, but it may also reduce vitamin D production. In theory, wearing sunscreen could cause vitamin D deficiency.
Studies suggest that putting on low SPF sunscreen does not cause vitamin D deficiency, but we do not know if regularly applying SPF 50+ sunscreen affects vitamin D.
The Sun-D Trial is the first large trial to investigate the effect of applying SPF 50+ sunscreen on Vitamin D.
Half of the participants in the Sun-D trial (decided randomly) will be given sunscreen to apply every day for most of one year. The other half will continue with their usual sun protection behaviour.
All participants will have to:
- Complete short online surveys each month for one year; AND
- Provide a blood sample so we can measure vitamin D (just like having a regular blood test) 3 times in the year.