JMIR Publications

ABSTRACT

Background:

Long-term sun exposure is one of the risks faced by outdoor swimmer which can cause sunburn. Using sunscreen is one of the ways to prevent sunburn, however, physical activity can trigger sweat, friction, and water washing that can interfere sunscreen efficacy and decreasing its sun protection factor (SPF). Sunscreens are classified into inorganic and organic based on their filter. Organic sunscreen has better bond to the skin compared to inorganic sunscreen which forms a barrier above the skin layer that made it easier to remove. Organic sunscreen lasts longer than inorganic sunscreen when used in physical activities, but it has limited spectrum, more photolabile, and more allergenic.

Objective:

To determine the persistency of SPF 30 between inorganic and organic sunscreen after 1,5 hours-swimming durations.

Methods:

This study is a randomized, split-body, double-blind, clinical trial to evaluate the persistency of SPF 30 of the inorganic versus organic sunscreens in swimmers. Randomization were done to allocate the subject into treatment groups. Each subject will receive two treatments; inorganic and organic sunscreen, which is applied to the back area. The difference in SPF of inorganic and organic sunscreens was no different if the p-value for the paired test was >0.05 and the upper limit of the confidence interval did not exceed 4 SPF.

Results:

Twenty-two swimmers were enrolled in this study. Based on the analysis there was no significant difference between the SPF of the two sunscreens before swimming (p=0.220). After swimming, there was a decrease in the SPF levels of both sunscreens; inorganic with a median of 27 (23-47) to 12.3 (8-19) and organic with a median of 30 (24-47) to 9.9 (6-19) which was statistically significant (p<0.0001). When compared between the SPF of inorganic and organic sunscreens after swimming, there was a statistically significant difference in the decrease in SPF levels between the two groups (p=0.017) and indicated a better SPF persistence of inorganic sunscreens when compared to organic sunscreens.

Conclusions:

There is a decrease in the SPF levels of inorganic and organic sunscreens after 1.5 hours swimming with a better persistence of inorganic sunscreens compared to organic sunscreens. Clinical Trial: This trial has been registered into ClinicalTrials.gov with identifier number [NCT04618536] and has been approved by clinical research ethics committee of Faculty of Medicine Universitas Indonesia.