Skin cancer is the most common type of cancer, with the greatest burden in the United States, Europe, Australia, and New Zealand. New cases and deaths from melanoma, the most severe form, have been increasing dramatically. Although invasive melanoma accounts for 1 percent of all skin cancer cases, it is estimated to cause more than 80 percent of skin cancer deaths (Am Fam Physician 2018;98(2)online).
Skin cancer is substantially preventable by reducing unprotected exposure to ultraviolet radiation (UVR). Although exposure to UVR is important for production of vitamin D, a considerable body of observational evidence demonstrates that UVR exposure represents the major environmental risk factor for all types of skin cancer. Moreover, sun exposure and sunburns during childhood and adolescence have been shown to play a critical role in the etiology of all skin cancer types (Ann Epidemiol 2008; doi: 10.1016/j.annepidem.2008.04.006), and melanoma since children's skin is more sensitive to UVR.
The Surgeon General and World Health Organization have outlined five guidelines to enhance sun protection (https://bit.ly/3rAZ2et). These sun-protection behaviors include wearing protective clothing, wearing sunglasses and a hat, seeking shade, avoiding peak sunlight hours, and the use of broad-spectrum sunscreen.
Behavioral & Environmental Factors
No single strategy in isolation can solve the problem. Although educational interventions have demonstrated positive effects, it is important to acknowledge that behavior can also be inevitably triggered by environmental characteristics. A person's environment can be described by both different levels of influence (i.e., micro/family setting or macro/community level), as well as by different types of the environment (i.e., economic, social, political, or physical).
Furthermore, from a behavioral development angle, it is vital that children learn to implement sun protective approaches at an early age, rather than get familiar with these behaviors in later life, as harmful habits then may already have been established (BMC Public Health 2019; https://doi.org/10.1186/s12889-019-7382-0). Hence, it is imperative to develop a comprehensive approach in skin cancer prevention strategies among children, targeting both behavioral and environmental factors to enhance sun safety behaviors.
Over the years, several types of interventions have been developed to encourage various sun protection behaviors among children and adolescents in various outdoor settings; however, stand-alone effectiveness of environmental elements is still lacking insight. To compose a mix of effective strategies targeting future skin cancer prevention interventions optimally, identification of effective environmental components is necessary.
Environmental Sun Safety Interventions
Recently, a systematic literature study conducted by Thoonen and colleagues, was the first to examine stand-alone effects of various types of environmental sun safety interventions among children and adolescents (Int J Environ Res Public Health 2020 doi: 10.3390/ijerph17020529). The extensive systematic literature search was performed using four scientific databases and one academic search engine.
The research team followed the PRISMA guidelines for systematic reviews to facilitate the reproducibility of this study. Studies eligible for inclusion met the following criteria: 1) stand-alone effects on socio-cognitive determinants, sun safety behaviors, UVR exposure, and sunburn and nevi incidence; 2) among children aged between 0 and 18 years; 3) outdoor and school settings; 4) physical environmental, policy, economic, and/or socio-cultural interventions; and 5) including intervention designs with at least one comparison group. Studies that were written in non-English and those that were performed prior to 1900 were excluded.
In total, seven studies were included. Free provision of sunscreen was most often the environmental component of interest (four studies), the second most used intervention type was an adaptation in the physical environment, consisting of shade provision such as supplying shaded areas, portable shade tents, or planted trees (three studies), while the provision of UV-protective clothing and accessories was included in one study.
The results of the included studies revealed that, while sunscreen provision was the most frequently mentioned intervention, it has shown inconsistent results in terms of effectiveness. Sunscreen use alone is not sufficient for UVR protection and is currently deemed a supplementary recommendation besides other sun safety practices.
The inclination of measuring sunscreen use preceding to shade-seeking and clothing behavior in the studies agrees with a universal popularity of sunscreen application. Evidence regarding shade provision on shade-seeking behavior was the most promising and consistent in increasing shade-seeking behavior. Because supplying shade provides intervention opportunities in various settings, in both schools and public areas, the authors recommend integrating shade provision in sun safety interventions for children. Evidence of effects of environmental interventions on other outcomes such as incidence of nevi were variable, thus consistent conclusions could not be drawn.
Limitations of the study include the number of eligible studies that specifically met the investigators criteria turned out limited, and years of publication of the included studies showed a shortage in recent studies conducted, which demonstrates a possible decrease in interest in environmental components in skin cancer prevention interventions.
Additionally, regarding the setting in which interventions were implemented, the school setting was most often used. However, other settings can also be of considerable importance regarding enhancing sun safety such as recreational settings. Children specifically are at high risk of receiving large amounts of UVR at playgrounds due to unavailability of shaded areas, noted the authors. These findings accentuate the importance of intervening in recreational settings.
Overall, although more research is necessary to consolidate the findings, the review highlighting the potential role of environmental components in skin cancer prevention interventions demonstrated overall encouraging results of environmental interventions in five of the seven included studies. Future initiatives should be targeted at children and adolescents in various outdoor settings.
Dibash Kumar Das is a contributing writer.