Professor Peter Soyer, Professor of Dermatology at the Uni of Qleensland explains how the skin is damaged over time by UV exposure - The Conversation, 11 Jan 2019:
There’s a lot to be said for sunshine – both good and bad. It’s our main source of vitamin D, which is essential for bone and muscle health. Populations with higher levels of sun exposure also have better blood pressure and mood levels, and fewer autoimmune diseases such as multiple sclerosis.
On the other hand, excess UV exposure is estimated to contribute to 95% of melanomas and 99% of non-melanoma skin cancers. These skin cancers account for a whopping 80% of all new cancers each year in Australia.
Like any medicine, the dose counts. And in Australia, particularly in the summer, our dose of UV is so high that even short incidental exposures – like while you hang out the washing or walk from your carpark into the shops – adds up to huge lifetime doses.
Fortunately, when it comes to tanning, the advice is clear: don’t. A UV dose that’s high enough to induce a tan is already much higher than the dose needed for vitamin D production. A four-year-long study of 1,113 people in Nambour, Queensland, found no difference in vitamin D levels between sunscreen users and sunscreen avoiders.
See full article here.
See also Your Skin, Vitamin D and the Sun