Is the Global Solar UV Index an effective instrument for promoting sun protection? A systematic review.

Exposure to ultraviolet radiation is an important risk factor for skin cancer. The Global Solar Ultraviolet Index (UVI) was developed as a tool to visualize the amount of harmful radiation and to encourage people to use sun protection. We conducted a systematic review of the effectiveness of the UVI. We employed a comprehensive search strategy to explore the impact of the UVI on five outcome categories. Twenty-seven of a total of 260 studies met our inclusion criteria; data extraction and quality appraisal were undertaken for 25 studies, comprising 3 randomized controlled trials, 2 non-randomized intervention studies and 20 cross-sectional studies. Nearly half of these studies were from Australia and New Zealand. We found low to intermediate levels of UVI awareness and low levels of UVI understanding. Studies rated moderate or strong suggest that the UVI does not influence knowledge, attitudes, sun protection behavior or sun exposure. Overall, the findings imply that the UVI, as currently implemented, has not been successful at improving sun protection practices and reducing sun exposure among the population at large. Drawing on experience with theory-based sun protection programs, we advocate for more realistic expectations of what the UVI can and cannot achieve.