Validity and Use of the UV Index

Abstract

The adequacy of the UV Index (UVI), a simple measure of ambient solar ultraviolet (UV) radiation, has been questioned on the basis of recent scientific data on the importance of vitamin D for human health, the mutagenic capacity of radiation in the UVA wavelength, and limitations in the behavioral impact of the UVI as a public awareness tool. A working group convened by ICNIRP and WHO met to assess whether modifications of the UVI were warranted and to discuss ways of improving its effectiveness as a guide to healthy sun-protective behavior. A UV Index greater than 3 was confirmed as indicating ambient UV levels at which harmful sun exposure and sunburns could occur and hence as the threshold for promoting preventive messages. There is currently insufficient evidence about the quantitative relationship of sun exposure, vitamin D, and human health to include vitamin D considerations in sun protection recommendations. The role of UVA in sunlight-induced dermal immunosuppression and DNA damage was acknowledged, but the contribution of UVA to skin carcinogenesis could not be quantified precisely. As ambient UVA and UVB levels mostly vary in parallel in real life situations, any minor modification of the UVI weighting function with respect to UVA-induced skin cancer would not be expected to have a significant impact on the UV Index. Though it has been shown that the UV Index can raise awareness of the risk of UV radiation to some extent, the UVI does not appear to change attitudes to sun protection or behavior in the way it is presently used. Changes in the UVI itself were not warranted based on these findings, but rather research testing health behavior models, including the roles of self-efficacy and self-affirmation in relation to intention to use sun protection among different susceptible groups, should be carried out to develop more successful strategies toward improving sun protection behavior.

A Randomized Controlled Trial of a Mobile Medical App for Kidney Transplant Recipients

“…A threshold UVI of 3 or more was exceeded on 118 of 123 days of this study; therefore, there was sufficient ambient sunlight to darken skin. 16 Forearm skin pigmentation was significantly reduced in the intervention group with skin types II-IV, which confirms the self-reported increase in participants' use of sun protection. Forearm pigmentation did not achieve a significant difference between the intervention and control groups for those with skin types V to VI.…”

Erythemal ultraviolet solar radiation doses received by young skiers

“…This result emphasises the need for protective measures against solar radiation, such as high protection sunscreen (30 or higher), sunglasses, a hat and high quality protective clothing when performing this type of outdoor physical activities. The results of this study are also consistent with the guidelines given by the ICNIRP working group 79 , which recommends sun protection for those who plan to be outdoors for prolonged periods at UVI Levels 1 and 2.…”

School students’ knowledge and understanding of the Global Solar Ultraviolet Index

“…An ICNIRP Working Group decided that changes to the UVI itself were not warranted. [18] However, if a basic comprehension of the UVI metrics is missing, it is unlikely to have a positive influence on sun-related attitudes and behaviours. Teaching about the UVI should begin at school, and this has been the practice in many NZ primary and intermediate schools, although standardised SunSmart Schools curriculum resources, including substantial content about the UVI, were not commissioned and promoted online until 2014.…”