Real-Time UV Measurement With a Sun Protection System for Warning Young Adults About Sunburn: Prospective Cohort Study

Abstract

Background: Melanoma is attributable to predisposing phenotypical factors, such as skin that easily sunburns and unprotected exposure to carcinogenic UV radiation. Reducing the proportion of young adults who get sunburned may reduce the incidence of melanoma, a deadly form of skin cancer. Advances in technology have enabled the delivery of real-time UV light exposure and content-relevant health interventions.

Objective: This study aims to examine the feasibility of young adults performing the following tasks daily: wearing a UV dosimeter, receiving text messages and real-time UV-B doses on their smartphone, and responding to daily web-based surveys about sunburn and sun protection.

Methods: Young adults aged 18-39 years (n=42) were recruited in the United States in June 2020 via social media. Participants received the UV Guard sun protection system, which consisted of a UV dosimeter and a smartphone app. During 3 consecutive periods, intervention intensity increased as follows: real-time UV-B dose; UV-B dose and daily behavioral facilitation text messages; and UV-B dose, goal setting, and daily text messages to support self-efficacy and self-regulation. Data were self-reported through daily web-based surveys for 28 days, and UV-B doses were transmitted to cloud-based storage.

Results: Patients' median age was 22 years (IQR 20, 29), and all patients had sun-sensitive skin. Sunburns were experienced during the study by fewer subjects (n=18) than those in the preceding 28 days (n=30). In July and August, the face was the most commonly sunburned area among 13 body locations; 52% (22/42) of sunburns occurred before the study and 45% (19/42) occurred during the study. The mean daily UV-B dose decreased during the 3 periods; however, this was not statistically significant. Young adults were most often exercising outdoors from 2 to 6 PM, walking from 10 AM to 6 PM, and relaxing from noon to 2 PM. Sunburn was most often experienced during exercise (odds ratio [OR] 5.65, 95% CI 1.60-6.10) and relaxation (OR 3.69, 95% CI 1.03-4.67) relative to those that did not exercise or relax in each category. The self-reported exit survey indicated that participants felt that they spent less time outdoors this summer compared to the last summer because of the COVID-19 pandemic and work. In addition, 38% (16/42) of the participants changed their use of sun protection based on their app-reported UV exposure, and 48% (20/42) shifted the time they went outside to periods with less-intense UV exposure. A total of 79% (33/42) of the participants were willing to continue using the UV Guard system outside of a research setting.

Conclusions: In this proof-of-concept research, young adults demonstrated that they used the UV Guard system; however, optimization was needed. Although some sun protection behaviors changed, sunburn was not prevented in all participants, especially during outdoor exercise.

Trial registration: ClinicalTrials.gov NCT03344796; http://clinicaltrials.gov/ct2/show/NCT03344796.

Keywords: UV dosimeter; health promotion technology; melanoma; mobile phone; preventive medicine; sun protection; sunburn.

Figure 1

Wireless UV-B dosimeter worn on the wrist (arrow indicates a UV-B photodiode).

Figure 2

Smartphone screen showing the real-time UV-B dose in relation to the threshold dose at which the participant would get a sunburn; the predicted weather, including cloud cover; UV index; and temperature.

Figure 3

Example of a self-reported measure for clothing covering the head and the neck. N/A: not applicable.

Figure 4

Mean proportions of each of the days spent outside by the sample for any activity during the 3 periods stratified by 2-hour periods.

Figure 5

Mean proportions of each of the days spent outside by the sample for exercise during the 3 periods stratified by 2-hour periods.

Figure 6

Mean proportions of each of the days spent outside by the sample relaxing during the 3 periods stratified by 2-hour periods.

Figure 7

Mean proportions of each of the days spent outside by the sample walking during the 3 periods stratified by 2-hour periods.

Figure 8

Mean proportions of each of the days spent outside by the sample with an unprotected face during the 3 periods stratified by 2-hour periods.