Regular Sunscreen Use and Risk of Mortality: Long-Term Follow-up of a Skin Cancer Prevention Trial

Introduction: Sunscreen is widely used to protect the skin from harmful effects of sun exposure. However, there are concerns that sunscreens may negatively affect overall health. Evidence of the general safety of long-term regular sunscreen use is therefore needed. Methods: The effect of long-term sunscreen use on mortality was assessed over a 21-year period (1993–2014) among 1,621 Australian adults who had participated in a randomized skin cancer prevention trial of regular versus discretionary sunscreen use (1992–1996). In 2018, an intention-to-treat analysis was conducted using Cox proportional hazards regression to compare death rates in people who were randomized to apply sunscreen daily for 4.5years, versus randomized to use sunscreen at their usual, discretionary level. All-cause mortality and deaths resulting from cardiovascular disease, cancer, and other causes were considered. Results: In total, 160 deaths occurred in the daily sunscreen group compared with 170 deaths in the discretionary sunscreen group (hazard ratio=0.94, 95% CI=0.76, 1.17); 59vs 76 cardiovascular disease deaths (hazard ratio=0.77, 95% CI=0.55, 1.08), 63vs 58 cancer deaths (hazard ratio=1.09, 95% CI=0.76, 1.57), and 45vs 44 deaths resulting from other causes (hazard ratio=1.02, 95% CI=0.67, 1.54) occurred respectively. Conclusions: Regular use of a sun protection factor 16 sunscreen on head, neck, arms, and hands for 4.5years did not increase mortality.