Some heavy lifting for the claim that skin impacts health comes from this: > it's thought that intrinsic factors are responsible for the tiniest fraction of th

Some heavy lifting for the claim that skin impacts health comes from this: > it's thought that intrinsic factors are responsible for the tiniest fraction of the classic "aged" look, while UV light is responsible for over 80% of visible skin changes. Here's the result from the study this links to: "By calculating statistical correlations between the four clinical clusters (wrinkles/texture, ptosis, vascular disorders, and pigmentation disorders), and real age and apparent age on the one hand and heliodermal status on the other hand, we identified a link between each clinical cluster and aging and the photoaging process. By comparing evaluations of clinical signs between the two groups for each 10-year cluster, we demonstrated that whatever the age, a prevalence of pigmentation disorders for the sun-seeking group (ie, pigmentation) is strongly linked to ultraviolet exposure. Meanwhile, clinical signs of ptosis are linked more to chronological aging and do not present differences between the two groups, nor, therefore, photoaging. Wrinkles and texture are affected by the two aging processes. Finally, clinical signs of vascular disorders present no evolution with age." I guess since UV impacts pigmentation and partially wrinkles, they add that up to 80%, but I see no hard number given for % impact on wrinkles/texture. One problem I can immediately see is that people are judged to be older primarily based on wrinkling, not pigmentation. Though it may be uncommon to notice age spots absent of significant wrinkling. I don't see a convincing case that unprotected skin is correlated with mortality risk moreso than poor health is correlated with aged skin.