Sun Protection by Beach Umbrella vs Sunscreen With a High Sun Protection Factor: A Randomized Clinical Trial
Ou-Yang H, Jiang LI, Meyer K, Wang SQ, Farberg AS, Rigel DS
JAMA Dermatol. 2017;153:304-308
Sunscreen use reduces the risk for nonmelanoma and melanoma skin cancers, chronic actinic damage, and acute phototoxic reactions. Nevertheless, many of those at risk for skin cancer—often influenced by professional and social media sources—are reluctant to apply sunscreen due to perceived but unsubstantiated health risks; these include paradoxical carcinogenicity, nanoparticle-induced skin and organ toxicity, vitamin D deficiency, and concerns about benzophenone-induced hormonal disruption.[2,3]
As public concern about the safety of sunscreens grows, more people are opting for "natural" protection against sunburns and tanning, relying more on ultraviolet (UV)-blocking clothing and shading devices such as parasols and beach umbrellas. To date, few studies[4,5] have attempted to quantify shade as a photoprotective strategy, and until now, none have compared the efficacy of shading devices such as beach umbrellas with that of sunscreen application.
Ou-Yang and colleagues tried to measure sunburn protection given by a standard beach umbrella versus application of a popular commercial sunscreen lotion with sun protection factor (SPF) of 100. They conducted this evaluator-blinded clinical study in a high-UV setting (midday on a sunny Texas beach in mid-August), using 81 healthy adult volunteers (56 female; mean age, 41 years) with Fitzpatrick skin types I (n=1), II (n=42), or III (n=38).
Study participants were randomly assigned to sunscreen or a beach umbrella. Groups were asked to stay on the beach for 3.5 hours, with all evaluated body sites uncovered (face, back of neck, upper chest, arms, legs). Half of the participants used beach umbrellas for sun protection while the other half applied the sunscreen with no shading. They were then evaluated for sunburn 22-24 hours after sun exposure.
Both umbrella and sunscreen groups showed increased global sunburn scores compared with baseline; the difference was significantly greater for the umbrella group versus the sunscreen group (0.75 vs 0.05; P < .001).
Erythema in one or more sites developed in 78% of the umbrella group versus 25% of the sunscreen group (P < .001).
Grade 2 sunburns ("redness clearly caused by UV rays") developed in 17 participants in the umbrella group versus two in the sunscreen group.
This study clearly showed that application of high-SPF sunscreen offers better sunburn protection than beach umbrella use alone. As the investigators noted, "real-life" beach umbrella use is likely to be less effective at protecting against sunburns because study volunteers optimally positioned their beach umbrellas to minimize reflected and scattered UV light exposure.
Of note, sunscreen use did not completely prevent sunburn, even though volunteers applied the lotion in an optimal fashion (applied liberally,15 minutes before beach exposure, and reapplied at least every 2 hours, without swimming). Because real-life sunscreen use would be less effective at preventing sunburns, those anticipating intense sun exposure should be encouraged to use both sunscreen and shade, ideally combined with UV-protective clothing (ie, hats, T-shirts).
The main take-home message is: For patients who insist that sitting under a beach umbrella will give them adequate sunburn protection, this study proves otherwise.
Medscape Dermatology © 2017 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Sunscreen or Sun Screen? - Medscape - Apr 21, 2017.