Application patterns among participants randomized to daily sunscreen use in a skin cancer prevention trial

Background: Despite many investigations of sunscreen use, there have been few among adults in the community at large. Better understanding of sunscreen application patterns will lead to more strategic skin cancer prevention strategies among sun-exposed populations. Objective: To explore patterns of sunscreen use, particularly the quantity of sunscreen used and the application frequency, among participants in a community-based sunscreen intervention. Design: Follow-up of patterns of sunscreen use over 4.5 years. Setting: Nambour, a subtropical town in Queensland, Australia. Participants: People drawn randomly from the electoral register who were later randomized as part of a skin cancer prevention trial. Interventions: Daily application of a standard sun protection factor 15+ broad-spectrum retail sunscreen to the head and neck, arms, and hands. Outcome Measures: Frequency of application of sunscreen, weight of sunscreen applied, and quantity applied per unit area of skin. Results: Fifty-six percent of participants reported applying sunscreen on at least 5 days per week, with 27% using sunscreen infrequently on 2 or fewer days per week. The median daily amount of sunscreen applied averaged over the duration of the trial was 1.5 g/d (range, 0-7.4 g/d). The median quantity of sunscreen applied was 0.79 mg/cm(2), which was less than half the amount needed to achieve the labeled sun protection factor. Conclusions: It is possible to implement the daily application of sunscreen in sun-exposed populations, although protection would be increased if the quantity of sunscreen applied were greater.