Modeling acute and cumulative erythemal sun exposure on vulnerable body sites during beach vacations utilizing behavior-encoded 3D body models

Is sunscreen alone effective at preventing sunburn on a high-solar beach vacation: A modeling study?

Beach holidays in areas of strong sunlight are popular and sunscreen is often the primary means of photoprotection favored by many people. The object of this study was to estimate how effective sunscreen is in preventing sunburn under high ultraviolet (UV) levels. We used a computational model to determine how the quantity, frequency, substantivity, and labeled SPF of applied sunscreens impact on the predicted erythemal response in unacclimatized skin over the course of a 7-day holiday in a high-solar environment. Our results indicated that sunscreen on its own may be insufficient to prevent sunburn in white skin on a sun-seeking holiday that combines prolonged exposure with high UV levels. Nevertheless, sunscreens have a valuable role to play on a beach holiday especially if an SPF30 or higher is chosen, the product is applied liberally and uniformly, application is started early into the sun exposure period and repeated at 2-hourly intervals throughout the day, and the product binds well to the skin. The main limitation of our investigation is that it is not an observational study but rather a computational model and while all models are wrong, some, including this one, are useful.

A numerical model for quantifying exposure to natural and artificial light in human health research

Various skin and ocular pathologies can result from overexposure to ultraviolet radiation and blue light. Assessing the potential harm of exposure to these light sources requires quantifying the energy received to specific target tissue. Despite a well-established understanding of the light-disease relationship, the quantification of received energy in diverse lighting scenarios proves challenging due to the multitude of light sources and continuous variation in the orientation of receiving tissues (skin and eyes). This complexity makes the determination of health hazards associated with specific lighting conditions difficult. In this study, we present a solution to this challenge using a numerical approach. Through the implementation of algorithms applied to 3D geometries, we created and validated a numerical model that simulates skin and ocular exposure to both natural and artificial light sources. The resulting numerical model is a computational framework in which customizable exposure scenarios can be implemented. The ability to adapt simulations to different configurations for study makes this model a potential investigative method in human health research.

Exploratory study on the body distribution of skin color, pigmentation and, degree of tan in Central European Caucasian Women

It is well known that skin color varies by body site and with season. However, little quantitative data on the topography of skin color and pigmentation are available. Therefore, exploratory cutaneous colorimetric measurements in 20 in central European Caucasian women aged 20 to 60 years have been made at 18 body sites. Tri-stimulus L*a*b*-values, hue, and chroma are considered to describe skin color. Based on the "Individual Typology Angle", the "Degree of Tan" was introduced to quantify the difference between constitutive and facultative pigmentation. Measurements were done in late winter and early summer to estimate potential changes by solar ultraviolet radiation. These measurements made evident that skin color obviously differs across the body in late winter. Even nearby body sites can be recognized as differently colored. A remaining degree of tan was found at permanent and intermittent exposed body sites. The remaining tan was not most pronounced at the permanently exposed sites but on the intermediate ones like the shoulder. In early summer, the degree of tan has most developed at the hands, arms, and instep, followed by the face. This study showed that besides basic differences between body sites in winter, accumulation, and degradation of tan also vary between body sites.

When should sunscreen be applied: The balance between health benefit and adverse consequences to humans and the environment

OBJECTIVE

To propose a strategy for using sunscreens that optimizes the balance between skin health and adverse effects to humans and the environment.

METHODS

A model was developed to explore the relationship between sunscreen usage and personal sun exposure throughout the year in populations resident at different latitudes.

RESULTS

There is little biological justification in terms of skin health for applying sunscreen over the 4-6 winter months at latitudes of 45° N and higher, whereas year-round sunscreen is advised at latitudes of 30° N and lower. Avoiding sunscreen application at times when it is biologically unnecessary results in an annual reduction in sunscreen use of 25%. Furthermore, using products containing UV filters over the winter months at more northerly latitudes could lead to a higher number of people with vitamin D deficiency. The single largest use of sunscreen is on a sun-seeking holiday and encouragement to make more use of clothing and shade would appreciably reduce the sunscreen burden to the environment.

CONCLUSION

We need to use sunscreens wisely so that we gain the health benefit from their use while at the same time limiting possible harm to ourselves and the environment.