CIE 2018 Topical Conference on Smart Lighting, Taipei, Chinese Taipei, April 24 – 28, 2018
Abstract Submission Open

CIE Training Programme

Each new Technical Report and Standard of the CIE will be complemented by a Training Unit. You can join in either in real life or via our live streaming facility or download the recorded and edited version at later point at your convenience.


The upcoming Training on CIE 201:2011 Recommendations on Minimum Levels of Solar UV Exposure will take place on Wednesday, May 16, 2012 between 09:00am and 05:00pm in Vienna at the CIE Central Bureau and will be chaired by Dr Wim Passchier.


Register here for participation in real life, our live streaming facility is readily available via this link.  Please, note: places are limited and will be assigned on a first come, first serve basis.  Registration for both, real-life and live streaming, is open till April 30, 2012.


Price: EUR 600,-- + 20% VAT. (On discounts for students and corporate packages for companies please contact the CIE Central Bureau at




In this tutorial Wim Passchier, chair of CIE’s Technical Committee 6-58, discusses the work of his committee in preparing guidance for healthy sun exposure. The sun and sunlight is a determining factor in people’s life and the attitudes of people and changes in these attitudes in the course of history reflect this. In Caucasian populations a tanned skin was considered both as a sign of health life and as a symbol of the lower social classes that often were outdoor workers. In the beginning of the 20th century sunlight was considered a cure for infectious diseases and ‘extra’ sunlight was provided by sun lamps in hospitals and schools. With the concerns about the degradation of the stratospheric ozone layer, that would lead to increasing exposure to sun light and in particular to the sun’s ultraviolet rays, dermatologists warned against too much sun. The ultraviolet radiation was considered as a major factor in the incidence of skin cancer, including melanoma.


However, the same ultraviolet rays also helped maintain the vitamin D status of humans. Epidemiological studies also indicated that sun exposure would reduce the incidence of various types of cancer, other than skin cancer. It was hypothesized that vitamin D might play a role in this respect.


These findings led to the suggestion that too much sun exposure may be harmful, but that too little exposure might have a negative impact on health as well. This issue was put on the desk of TC 6-58 and defined as follows:

The fact that man cannot do entirely without UV is accepted by most scientists active in this field, but is not as well-known as the widely accepted view that UV exposure should be limited to a sensible level thus avoiding or minimizing risks. The TC will formulate recommendations for a lower limit of UV exposure commensurate with good health.


The committee consisted of physicists, epidemiologists, immunologists, biophysicists, physicians and environmental health scientists.


It soon concluded that recommending a limit in a strict sense would not be possible. As there are no thresholds for both the harmful and the beneficial effects of sun exposure —or at least they are unknown— the question is how to balance the pros and cons of sun exposure. On the one hand this is not a question that can be solved by scientists alone. On the other hand geographical, seasonal, social and cultural factors are highly relevant in individual and population sun exposure. Especially the social and cultural factors were rather outside the domain of expertise of the committee. So the committee decided to:

  • assess the scientific evidence for beneficial effects of sun exposure and rate the evidence in a consistent way;
  • prepare recommendations for ‘healthy sun exposure’ that should be further developed nationally and regionally.


The conclusions and recommendations of the committee can be summarised as:

The committee has found considerable evidence to deem it plausible that sun 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.


The committee 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 findings of the committee were underpinned with extensive literature reviews, prepared by the committee members. These reviews are also part of the committee’s report.


The work and report of the committee should lead to further work. As especially the knowledge of the role of vitamin D in maintaining health and the role of sun exposure in keeping vitamin D status at required levels, are developing rapidly, the science part of the committee’s report should be updated in a few years' time. Whether this is a task of the CIE or would be more within the scope of WHO remains to be determined. An important task of the CIE, possibly in cooperation with WHO, may be the extension of WHO’s UV index to include the beneficial effects of sun exposure. This would be helpful in communicating harms and benefits of actual sun exposure to the public. Finally the CIE might address the question whether sun lamp exposure may compensate for a lack of sun exposure.


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