CIE 201:2011

This Technical Report addresses the issue of sensible exposure to solar ultraviolet (UV) radiation. The scientific evidence of beneficial effects of solar exposure has been reviewed, in particular on the incidence and mortality to cancers other than skin cancer. Although the evidence is not unequivocal, the committee has found considerable evidence to deem it plausible that solar exposure may reduce the incidence and mortality of colorectal cancer. The evidence for similar effects on breast and prostate cancer and on melanoma is less, but such effects are considered as plausible, too. Possibly the production of vitamin D plays a role in this respect.

Based on a review of the evidence of both the beneficial and the harmful effects of solar exposures it is concluded that people should not shun the sun, even not at noon. However, levels well below sunburn thresholds are generally sufficient to profit from the beneficial effects of solar exposure. Public health guidance should be developed on the basis of this evidence, but account should also be taken of prevailing solar UV levels that depend on latitude and time of the year and day. Special guidance may be necessary for dark skinned people that live at moderate latitudes and people that cover most of their bodies for cultural or religious reasons. The same holds for people who stay most of the time indoors.

The amount of solar exposure commensurate with good health depends on individual and population characteristics, as indicated above. To facilitate public health guidance it is recommended to extend the concept of the UV index promulgated by the World Health Organization to include the beneficial effects of solar exposure.

The report is split into two parts: The first part (Part I) gives guidance for a sensible exposure regime to profit from beneficial health impacts from moderate solar (UV) exposure, the second part (Part II) is a review of scientific data that underpin the guidance in Part I.

The publication is written in English, with a short summary in French and German.