Sun and ski holidays improve vitamin D status, but are associated with high levels of DNA damage

J Invest Dermatol. 2014 Nov;134(11):2806-2813. doi: 10.1038/jid.2014.223. Epub 2014 May 20.


Skin cancer is caused by solar UVR, which is also essential for vitamin D production. DNA damage (thymine dimers: T-T dimers) and vitamin D (25(OH)D) synthesis are both initiated by solar UVB. We aimed to investigate the simultaneous adverse and beneficial effects of solar UVB exposure in holidaymakers. Sun-seekers and skiers (n=71) were observed over 6 days through on-site monitoring, personal diary entries, and recording of personal UVB exposure doses with electronic dosimeters. Urine and blood samples were analyzed for T-T dimers and 25(OH)D, respectively. The volunteers had a statistically significant increase in vitamin D. There were strong associations between UVB exposure and post-holiday levels of T-T dimers and vitamin D, as well as between post-holiday T-T dimers and vitamin D. We conclude that UVB-induced vitamin D synthesis is associated with considerable DNA damage in the skin. These data, on two major health predictors, provide a basis for further field studies that may result in better understanding of the risks and benefits of "real life" solar exposure. However, vitamin D status can be improved more safely through the use of vitamin D dietary supplements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bathing Beaches
  • DNA Damage*
  • Female
  • Holidays
  • Humans
  • Male
  • Middle Aged
  • Pyrimidine Dimers / chemistry
  • Skiing
  • Skin / radiation effects
  • Skin Neoplasms / etiology
  • Sunlight / adverse effects*
  • Time Factors
  • Ultraviolet Rays / adverse effects*
  • Vitamin D / blood*
  • Vitamin D Deficiency / prevention & control*
  • Vitamin D Deficiency / therapy*


  • Pyrimidine Dimers
  • Vitamin D