Elsevier

Preventive Medicine

Volume 123, June 2019, Pages 71-83
Preventive Medicine

Review Article
Awareness, understanding, use, and impact of the UV index: A systematic review of over two decades of international research

https://doi.org/10.1016/j.ypmed.2019.03.004Get rights and content

Highlights

  • Awareness of the UVI varies widely across countries and regions.

  • Comprehension and use of the UVI to inform sun safety behaviors are uncommon.

  • Greater UVI awareness has sometimes been associated with more risky behaviors.

  • Few studies have evaluated interventions, and their results have been mixed.

  • More work is needed to help the public understand and use the UVI properly.

Abstract

The ultraviolet radiation index (UVI) was adopted internationally to raise awareness about and encourage the public to protect their skin from skin cancer. The current paper is a systematic review of over 20 years of research investigating awareness, comprehension, use, and impact of the UVI. Thirty-one studies were included from the USA, Canada, Europe, Australia, New Zealand, and elsewhere. Awareness of the UVI varies by country, with samples from some countries demonstrating high awareness. However, comprehension and use of the UVI to inform sun safety behaviors are typically much lower. In fact, greater UVI awareness has sometimes been associated with riskier UV-related behaviors such as intentional tanning. Fewer studies have evaluated interventions, and their results have been mixed. In summary, more research is needed to determine how to help the public understand and use the UVI for effective skin protection. This review offers suggestions for future use of and research with the UVI.

Introduction

Ultraviolet radiation (Hofbauer et al., 2010) can cause damage to the skin and eyes as well as suppress the immune system (Meves et al., 2003). UVR is the primary and most preventable risk factor for melanoma and non-melanoma skin cancers, which affect millions of people annually worldwide (Meves et al., 2003).

The UV index (UVI) was first developed in Canada in 1992 and adopted by the United States National Weather Service (NWS) and Environmental Protection Agency (EPA) as well as the World Meteorological Organization (WMO) and World Health Organization (WHO) in 1994. The UVI, a measure of the UVR levels at the Earth's surface, was published in 1995 as a result of a collaboration between the WMO, WHO, United Nations Environment Programme, the International Commission on Non-Ionizing Radiation Protection, and the German Federal Office for Radiation Protection (World Health Organization et al., 2002).

The UVI was intended to raise awareness and alert the public to the need for sun protection in order to reduce skin cancer risk. Although various versions of the UVI existed around the world before the standardization of the Global Solar UVI in 2002, they shared many similar qualities. Despite slight changes in color scheme, labeled exposure categories, and range of values, the actual UVR levels have not changed. The values of the UVI range from 1 to 11+ and are associated with varying recommendations for sun protection. For example, at a UVI value of 3, sun protection is recommended (i.e., seeking shade during midday, increasing clothing coverage, sunscreen and hat use), and at a UVI value of 8, extra sun protection is recommended (i.e., avoid being outdoors during midday, greater emphasis on sun protection) (World Health Organization et al., 2002).

Italia and Rehfuess (Italia and Rehfuess, 2012) conducted a systematic review of 25 studies to examine the effectiveness of the UVI and its impact on five outcome categories: familiarity, knowledge, attitude, behavior, and sun exposure. Overall, the researchers found low to intermediate levels of UVI awareness, low levels of UVI understanding, and minimal influence of UVI on sun protection. The authors concluded that implementation of the UVI had not resulted in widespread improvement of sun protection or reduction of sun exposure.

The purpose of the current paper is to explore UVI awareness, use, and impact on skin cancer risk and risk reduction behaviors by extending the work of Italia and Rehfuess (Italia and Rehfuess, 2012) and including newer studies (those conducted after 2010). In order to best expand upon their work, we modeled our search strategy and data collection methods on theirs. The current paper additionally presents studies related to UVI and various outcomes organized by geographic region (North America, Australia/New Zealand, Europe, and other countries) in order to help assess potential differences in study outcomes across regions with varying public health campaigns and UVR levels. Use and impact of the UVI in experimental and non-experimental studies were also distinguished.

Section snippets

Search strategy

Title/abstract search terms included any of the following terms: “UV index”, “UV indexes”, “UV indices”, “UVI”, “ultraviolet radiation index”, “UVR index”, “solar index”, “UV forecast*”, “UV radiation forecast*”, “ultraviolet index”, “solar ultraviolet index”, OR “solar ultraviolet radiation”. We also combined (using the Boolean operator ‘AND’) those terms with any of the following: “familiar*”, “understand” “comprehend”, “comprehension”, “know*”, “aware*”, “perception”, “perceive”, “attitude”,

Overview

See Fig. 1 for PRISMA flow diagram. Data extraction was conducted for 31 papers that were included in the systematic review. Papers were organized by outcome and into the following geographic regions: North America, Australia and New Zealand, Europe, and other. Ten papers addressed more than one outcome, and therefore, are reported more than once.

Random sampling was a common method of recruitment (n = 15), which can increase the representativeness of a sample. Other studies utilized a

Overall conclusions

The strengths of this paper include the systematic review of over 20 years of international research on UVI awareness, comprehension, use, and impact on sun-related behaviors. Many of the individual studies included large sample sizes but were also typically cross-sectional and self-report in nature. Limitations of the review are the inclusion of only papers published in the peer-reviewed English literature. Gray literature was not included, but almost all of the studies from the gray

Conflict of interest

The authors declare that there is no conflict of interest.

Acknowledgements

This work was supported by the National Institutes of Health [grants P30CA072720 and P30CA006927].

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