Health stakeholders have urged Australians to treat a study – which suggested that sunscreen chemicals could leach into users’ blood – with a pinch of salt
Researchers from the US Food and Drug Administration conducted a small, randomised trial of 24 healthy volunteers to determine bloodstream concentration of four active ingredients (avobenzone, oxybenzone, octocrylene and ecamsule) in four sunscreens applied four times per day for four days with blood samples collected from study participants over seven days.
According to the researchers, all four active ingredients were found in blood samples at levels exceeding the threshold recommended for toxicology testing.
The effect of these concentrations is unknown and further studies are needed to determine the clinical significance of these findings, they said, recommending that active ingredients in sunscreen absorbed into the bloodstream above a certain level undergo toxicology testing.
The authors pointed out that the trial had some limitations, including that it was conducted under indoor conditions without exposure to heat, sunlight or humidity, which may affect the rate of sunscreen absorption, and the study was not designed to look at differences in absorption by the type of sunscreen formulation, skin type or age of the user.
They also stressed that the results do not suggest that people stop using sunscreen.
The Australian Self Medication Industry said on Tuesday that sunscreens are safe and effective to use as one line of defence against skin cancer.
“The study did not replicate real-world conditions and was based upon a very small sample size of just 24 people,” said Steve Scarff, ASMI’s Regulatory and Legal Affairs Director.
“As noted in the study, these results do not indicate that individuals should refrain from the use of sunscreen.”
He pointed out that in Australia, sunscreens are regulated as medicines and as such must comply with the TGA’s standards.
Active ingredients must be evaluated for their safety by the TGA before they are approved for use in sunscreens and the emerging evidence is regularly reviewed to confirm their continued safety.
“Sunscreen is proven to reduce the incidence of melanoma and other skin cancers if applied regularly and liberally as directed on the label, alongside other skin protection measures,” Mr Scarff said.
“Ground-breaking University of Queensland research found that regular sunscreen use resulted in reduced melanoma rates. And recently, experts recommended that Australians should wear sunscreen every single day and apply it as part of their morning routine.”
Professor Sancha Aranda, CEO of the Cancer Council Australia, pointed out the study’s significant limitations.
“It’s important to put this study in context—the sample size was only 24 people, which is very small for any type of scientific research,” she said.
“The study also didn’t replicate real world conditions, for instance the sunscreen wasn’t used outdoors where we would expect the UV radiation would breakdown some of the active ingredients. The authors acknowledge that these results do not indicate that individuals should refrain from the use of sunscreen.
“Even if the sunscreen chemicals were absorbed, there is limited evidence to suggest that this would cause harm, but we do know that excess UV causes skin cancer and that sunscreen helps prevent skin cancer.
“It’s important that Australians continue to use sunscreen as one method of sun protection. Cancer Council recommends using an SPF30 or higher sunscreen that is broad spectrum, water resistant and TGA approved.”
However she warned that sunscreen should only be one weapon in Australians’ arsenal when it comes to sun protection.
“Sunscreen isn’t a suit of armour, and should only be used as the last line of defence. Whenever the UV level is three or above, the Cancer Council also recommends slipping on protective clothing, slapping on a broadbrim hat, slopping on sunscreen, seeking shade and sliding on sunglasses.”
Terry Slevin, Chair of Cancer Council Australia’s Occupational and Environmental Cancer Risk Committee, and President of the Public Health Association Australia, said that the take-home message from the study should be that “these results do not indicate that individuals should refrain from using sunscreen”.
“This is a small and preliminary study, involving 24 people, 14 of whom have strong natural sun protection through their skin type being dark,” he said.
“There remains no evidence of ‘clinical significance’. That means we still have no evidence that any such absorption has any adverse effects on any individual.
“The amount of sunscreen used in the study of 24 people was far in excess of what most people use. While they followed the recommended application levels, consistent evidence suggests most people use half or less of the recommended amount of sunscreen and many do not reapply once, let alone four times.
“As we move into the dry season in the northern part of Australia, people need to understand sunscreen remains a safe and effective means of protecting against the proven damage caused by excessive sun exposure.
“Further studies are needed to determine what this preliminary finding means for the health of Australians who rely on sunscreen as an effective way of protecting against the sun.”