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Monday, May 14, 2007

Review: Photoprotection

A review on photoprotection published early online in the Lancet examines environmental photoprotection, photoprotective clothing, sunscreens, controversies of sunscreens and clinical recommendations.

The key points from the article are as follows:

  • Behavioural measures such as wearing sun protective clothes and a hat, and reducing sun exposure to a minimum, must be preferred to sunscreens.
  • For improved protection, especially if midday summer exposure or tropical exposure is unavoidable, coverage of as much of the skin surface as possible, and correct application of a highly protective sunscreen over the remainder of the exposed skin, is very effective.
  • Application of a liberal quantity of sunscreen is by far the most important factor for effectiveness of the sunscreen, followed by uniformity of application and specific absorption spectrum of the agent used.
  • Application of organic sunscreens to exposed sites should be done 15–30 minutes before going out into the sun.
  • Waterproof or water-resistant sunscreens should be used to diminish the need for reapplication after swimming followed by towelling, friction with clothing or sand, and sweating.
  • The better protection against UVB provided by high SPF sunscreens (SPF > 15) has not been clearly proven to further protect against skin cancer, but the overall data has shown that a high SPF is preferable to low SPF sunscreen.
  • Broad-spectrum sunscreens with adequate UVA protection should be used, but there is no clear definition of what is “adequate.”
  • Sunscreens should not be abused in an attempt to increase time in the sun to a maximum.
  • Year-round daily use of sunscreen for people living in countries of low insolation, eg, UK and northern Europe can not be recommended, and sunscreens are best avoided during October to March.
  • There is some evidence that year-round application of sunscreens can be beneficial in preventing cancer and solar elastosis in areas of high insolation, such as Queensland, Australia, and Texas, USA.
[Editor's comment: media reports have picked up on the variable protection provided by different fabrics: unfortunately, the best protection seems to come from thicker, dark coloured, denim, wool, and synthetic (e.g. polyester) fabrics!]

Lancet, published early online 3 May 2007; DOI:10.1016/S0140-6736(07)60638-2
BBC News report.

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