Review of the Global Solar UV Index 2015 Workshop Report

Abstract

The Global Solar UV Index was developed as an easy-to-understand measure of the amount of biologically-effective ambient solar ultraviolet radiation (UVR) at different locations on the earth’s surface. Over the past few years, questions have been raised about the global applicability of the UV Index, about the evidence base for exposure risk thresholds and related protective measures, and about whether the overall impact of the UV Index could be improved with modifications. An international workshop was organized by several organizations, including the World Health Organization, to assess if current evidence was sufficiently strong to modify the UV Index and to discuss different ways it might be improved in order to influence sun-protective behavior. While some animal research suggests there may be no threshold effect, the relative importance of sub-erythemal doses of sunlight in causing skin cancer in humans remains unknown. Evidence suggests that regular use of sunscreen can prevent skin cancer and that sunglasses are an effective method of protecting the eyes from solar UVR. The UV Index as a risk communication tool continues to be useful for raising awareness and to support sun-protection behavior. Although there was agreement that guidance on the use of the UV Index could be improved, the workshop participants identified that strong health outcome-based human evidence would be needed as the basis for a revision. For the UV Index to be relevant in as many countries as possible, it should continue to be adapted to suit local conditions.

Public Health Messages Associated with the Low Exposure Category of the UV Index Need Reconsideration

“…A similar solution, though resulting from an analysis primarily focusing on high instead of low UVI values, has been proposed by other authors already [18]. Both the necessity for local adaptation and the possibility of including skin type and exposure duration in the UVI guidance have already been ascertained at a WHO UVI workshop in Melbourne in 2015 [19]. Up until now, this has not been implemented.…”

Environmental and genetic risk factors for MS: an integrated review

“…Exposure to cigarette smoking, low sun exposure, and childhood obesity are all modifiable risk factors that have been repeatedly and consistently associated with an increased risk of MS. Diets high in fish (and low in saturated fats) are recommended as part of a heart‐healthy diet and may also reduce the risk of MS. Thus, recommendations for at‐risk individuals are consistent with those for general health benefits and may reduce the risk of MS: avoidance of exposure to first‐ and second‐hand cigarette smoke; using the UV index to guide sun exposure in accordance with WHO guidelines, but ensuring regular sun exposure below a sunburning dose on most days of the week; and preventing childhood obesity by promoting a Mediterranean diet and exercise. Many clinicians also recommend vitamin D supplementation to prevent MS, although the hopes of general health benefits are probably limited aside from preventing rickets or osteoporosis in those individuals with extremely low levels (e.g.…”

Solar Radiation Exposure and Outdoor Work: An Underestimated Occupational Risk

“…A simplified measure of solar UV irradiance on a horizontal plan is represented by the UV index (UVI), which is an estimation of the risk of sunburn for different geographic regions adopted by the World Health Organization (WHO) in 1994. UVI is a linear numeric scale, ranging from 1 to 11+; the higher the value, the greater the potential for skin and eye damage [ 21 , 22 ]. The calculation of UVI is weighted for UV wavelengths to which the skin is most sensitive, according to the CIE action spectrum, so UVI represents a number linearly related to the intensity of sunburns produced by UVR at a specific place.…”

“…The calculation of UVI is weighted for UV wavelengths to which the skin is most sensitive, according to the CIE action spectrum, so UVI represents a number linearly related to the intensity of sunburns produced by UVR at a specific place. It has also to be considered that the most dangerous UVR bands reaching the skin are in the 295 to 325 nm wavelength range because the vast majority of UVR with shorter wavelengths, even if they have higher skin penetration and damage power, are absorbed by the earth’s atmosphere, in particular by the ozone layer [ 21 , 22 ]. Considering the linearity of the UVI scale, only from a theoretical point of view (under identical meteorological and environmental conditions, with the same person performing exactly the same activity with standard exposing behaviors and identical individual protections adopted), can it be said that the amount of UVR reaching a specific skin site during one hour of exposure to UVI 3 or half-hour exposure to UVI 6 is almost identical.…”