Sunscreen use at Danish beaches and how to improve coverage

Area of Science:

• Dermatology
• Public Health
• Photoprotection

Background:

• Ultraviolet radiation (UVR) exposure is a primary risk factor for skin cancer.
• Skin cancer incidence is rising globally, necessitating effective sun protection strategies.
• Understanding sunscreen use patterns among beachgoers is crucial for public health interventions.

Purpose of the Study:

• To assess sun protection knowledge and practices among Danish beachgoers.
• To develop and validate a method for evaluating sunscreen distribution on the skin.
• To test strategies for optimizing sunscreen application amount and body coverage.

Main Methods:

• Observational study of beachgoers' behavior regarding UVR exposure and sun protection.
• Development of a novel method using black light to quantify sunscreen application and distribution.
• Experimental testing of two distinct sunscreen application strategies: 'handful' rule and double application.

Main Results:

• Beachgoers often visit during peak UVR hours (noon-3 p.m.) and apply insufficient sunscreen (mean 0.57 mg/cm²), yielding a low effective SPF of 2.3.
• Women (78%) were more likely to use sunscreen than men (49%), with a median labeled SPF of 20.
• Both tested strategies increased sunscreen quantity; double application (1.10 mg/cm²) resulted in a higher effective SPF (5.2) and better body coverage (91%) compared to the 'handful' method (0.87 mg/cm², SPF 3.7, 80% coverage).

Conclusions:

• Current sunscreen application practices among beachgoers provide inadequate protection against UVR.
• Double application of sunscreen is a more effective strategy than the 'handful' rule for improving coverage and achieving a higher effective SPF.
• Public health messaging should emphasize thorough and potentially repeated sunscreen application to maximize photoprotection and minimize skin cancer risk.