Comparison of Sun Protection Factor (SPF) 30 Persistence between Inorganic and Organic Sunscreen in Swimmers: A protocol of Multicenter, Randomized, Non-Inferiority, Split-Body, Double-Blind Clinical Trial (Preprint)

Abstract

Outdoor swimming athletes are exposed to undesirable environmental conditions, such as long-term sun exposure. The risk of sunburn can still occur in this population due to the loss of sunscreen and an increase in the sensitivity of the skin to UV rays, particularly UVB, in wet conditions. There are two types of sunscreens based on the filter component, specifically organic and inorganic. Some previous trials showed that organic sunscreens had a longer shelf-life than inorganic after exercise due to their characteristics to bind better with the skin layer. Meanwhile, inorganic sunscreens tend to form layers on their skin’s surface so that they can be more easily removed. To our knowledge, no studies evaluate sunscreens' resistance, either inorganic or organic, after exercising in Indonesia.

We will conduct a randomized, split-body, double-blind, noninferiority, and multicenter clinical trial to evaluate the persistence of the inorganic versus organic sunscreens in swimmers. The primary objective is to assess whether inorganic sunscreen is as good as organic sunscreen in the field of the persistence of sunscreens after swimming for 1,5 hours.

Research subjects will be randomly selected from one swimming center in Cikini, Jakarta, Indonesia. An estimated 22 athletes in each group will be randomized using a computer-generated randomization method. We calculated the sample size using the difference in the average decrease in SPF levels that is considered significant based on the clinical judgment set by the researchers, which was 5. Neither the research subjects nor the researchers are aware of the type of sunscreen that was applied.

This study will test all procedures in preparation for conducting the main study, including several potential obstacles and challenges from the perspective of participating physicians and eligible swimmers. This study has been approved by the Ethical Committee Faculty of Medicine Universitas Indonesia and is funded by the International Publication Grant from Universitas Indonesia. Study results will be disseminated through publications in a peer-reviewed journal with Open Access format. This study will provide information about SPF 30 persistence in sunscreens and the best type of sunscreen to be used while swimming, particularly for athletes.

We expect the results of this study can be concluded as follows: 1. Decreasing number in the SPF level of inorganic and organic sunscreens after use swimming 1.5 hours. 2. The SPF resistance of inorganic sunscreens is better than sunscreen organic after being used to swim for 1.5 hours

This clinical trial has been registered into ClinicalTrials.gov with identifier NCT04618536 and Ethical Committee Faculty of Medicine Universitas Indonesia ID numbers 20-09-1037.