Enhancing sunscreen efficacy in the ‘real’ world?

Dynamic visualization of ultraviolet dose on skin with sunscreen applied using minimum erythema dose

BACKGROUND

Visualizing the ultraviolet (UV) dose on skin serve as an intuitive approach to ensure appropriate sunscreen usage and reduce the risk of erythema. UV dose is determined by a number of external factors, such as properties of sunscreens, weather, and type of outdoor activity. We propose a framework for visualizing UV doses that considers various external factors.

MATERIALS AND METHODS

First, the skin of a three-dimensional human model was represented using triangular meshes, and various static postures and dynamic motions were simulated to express outdoor activities. Then, we evaluated the persistency and insufficiency properties of sunscreen, which are time dependent and directly affect the effectiveness of the sunscreen skin protection factor (SPF) during UV exposure. Finally, to calculate the UV dose in real time, we tracked the trajectory of the sun and motion of the skin while considering the time-dependent properties of sunscreen.

RESULTS

An S/W system was implemented based on the proposed framework to visualize the distribution of UV doses through dynamic color changes in exposed skin areas. The color types include true colors, which represent the minimum erythema dose (MED), and pseudo colors representing states before 1 MED is reached. We devised various examples to discuss the usability of the proposed framework.

CONCLUSION

The system conveniently displays the MED according to an individual's skin phototype. When the properties of a wide range of commercial sunscreens are added to the system database, it is expected that the rate of appropriate sunscreen usage by customers will increase.

The Context of Sunburn Among U.S. Adults: Common Activities and Sun Protection Behaviors

INTRODUCTION

Sunburn increases skin cancer risk and is common among U.S. adults. However, little is known about the contexts in which sunburns often occur. The purpose of this study is to examine the contextual factors surrounding sunburns among U.S. adults.

METHODS

Cross-sectional data from a 2018 online panel survey were analyzed. A total of 4,088 panel members were recruited by mail using probability-based, random sampling by address. Respondents were asked about their most recent sunburn, and analyses were limited to those who remembered their most recent sunburn (N=3,106). Data were weighted to match the U.S. Current Population Survey proportions; analyses were conducted in 2018 and 2019.

RESULTS

Participants' age ranged from 18 to 93 years. About half (50.8%) were women, and most (82.3%) were non-Hispanic White adults. Swimming or spending time in water (32.5%), working outside at home (26.2%), traveling/vacationing (20.7%), and engaging in nonswimming physical activity (14.2%) were the most frequently reported activities. Using sunscreen on the face, neck, and chest (38.8%) and on the body (19.9%) and wearing sunglasses (34.2%) were the most frequently reported sun safety behaviors. Wearing clothes to the ankles (6.6%) and a long-sleeved shirt (4.5%) were least frequently reported.

CONCLUSIONS

This study provides new information about the contexts in which adult sunburns often occur, especially about contexts unrelated to intentional tanning, which was relatively infrequent. The results suggest the need to promote multiple forms of sun protection tailored to specific outdoor activities and develop innovative solutions for outdoor physical and aquatic activities, which present unique sun safety challenges.

Layering sunscreen with facial makeup enhances its sun protection factor under real-use conditions

BACKGROUND

The proper application of sunscreen is important to ensure protection of the skin against ultraviolet (UV) damage. Sunscreens are used in various ways in real world situations, which alters their UV protection efficacy. In this study, we simulated typical consumer use of sunscreen, which is often sequentially covered with facial makeup, in a laboratory study.

METHODS

We compared the sun protection factors (SPF) of sunscreen and makeup products after consecutive layering of the products.

RESULTS

The SPF of each sunscreen and makeup product was dramatically lower than stated on the label upon application of a typical amount used by a consumer, which is lower than recommended. For high-SPF products, the drop in effective protection was proportionally greater than those for the low-SPF products upon application of lower doses. However, layering sunscreen and makeup products greatly increased the effective SPF compared with that achieved by single application of each product, even when the amount of each product used was below the recommended level.

CONCLUSION

Layering sunscreen with makeup may compensate for insufficient sunscreen application in real-life conditions by providing an additional source of UV protection and improving the homogeneity of coverage. Our results suggest that recommending consecutive application of sunscreen and makeup products may be a practical and useful approach to improving UV protection that would not require additional steps in the facial care routines of many individuals.

The Role of Dispensing Device and Label Warnings on Dosing for Sunscreen Application: A Randomized Trial

Drug manufacturers are expected to provide labeling information needed to yield safe and effective product use. However, it is not clear that consumers dose sunscreen, an over-the-counter drug, appropriately; in fact, existing evidence suggests underdosing as a common phenomenon. The objective of this study was to evaluate the effect of dispensing device and labeling on self-administered doses of sunscreen in young adults. To investigate those effects, a 2 × 2 factorial laboratory experiment crossing dispensing device (two levels) with labeling treatment (two levels) was conducted. Participants applied sunscreen from each of the four treatments; dosing concentration, measured in mg/cm², served as the response variable. Participants (n = 94) were recruited on the campuses of Michigan State University (East Lansing, MI) and California Polytechnic State University (San Luis Obispo, CA). Each participant applied sunscreen from each unique treatment to sites on their arms and legs (four applications). Postapplication, a survey was completed to characterize demographics, risk perception, and sunscreen use patterns. Results indicate participants applied approximately 30% less sunscreen from the pump bottles than the squeeze bottles (difference estimate of 0.3059 mg/cm², standard error = 0.0607, p < .0001); there was no evidence of a difference based on label treatments. Post hoc recognition tests indicated only 55% of participants were able to recognize the two experimental labels they had viewed immediately following sunscreen application. Sunscreen application density was directly related to level of worry regarding skin cancer and frequency of sunscreen use (α = .05). Our results suggest the dispensing device used to deliver sunscreen impacts the dosage amount consumers apply.