June 04, 2013
By Genevra Pittman
NEW YORK (Reuters Health) Jun 04 - Using sunscreen every day may help protect against aging skin, according to a new study from Australia.
Although the benefits of sunscreen are well know when it comes to preventing sunburns and lowering skin cancer risks, researchers said rigorous studies were lacking on how sunscreen use affects photoaging.
Still, one dermatologist who wasn't involved in the new study said the findings just reinforce what skin doctors already know and tell their patients.
"If you ask most dermatologists... they'll tell you the two things they recommend for people who really want to avoid photoaging are, don't smoke and use sunscreen," said Dr. Alan Boyd, from Vanderbilt University Medical Center in Nashville.
"There are definitely a diminished number of people who have pre-cancerous (skin) changes if they are regular users of sunscreen," he told Reuters Health. "It's not too much of a leap to assume the signs and features of photoaging would follow hand in hand."
For the new study, Dr. Adele Green from the Queensland Institute of Medical Research and her colleagues analyzed data from 903 adults younger than 55 who were followed between 1992 and 1996.
Half of them were told to put sunscreen of SPF 15 or greater on their head, neck, arms and hands every morning, and to reapply when necessary. The others used sunscreen according to their own discretion.
At the start and end of the study, the researchers measured photoaging using the skin on the back of each person's left hand. They found that over four years, there were no detectable changes in the skin condition of people who were told to use sunscreen daily, once other sun-related factors were taken into account.
Australians in that group were 24% less likely to show any increased aging - clinical changes that might not be visible to the naked eye - than those who decided on their own when to wear sunscreen, Dr. Green and her colleagues reported June 3 online in the Annals of Internal Medicine.
Beta carotene, which was also given to some of the participants, did not seem to have any protective effect on skin aging, however.
Photoaging happens after long-term exposure to ultraviolet radiation, which penetrates the skin and can cause collagen to break down and DNA to mutate, said Dr. Brundha Balaraman, a dermatology researcher from the Washington University School of Medicine in St. Louis.
"This study effectively shows that daily sunscreen can reduce the signs of photoaging and photodamage," Dr. Balaraman, who also wasn't part of the research team, told Reuters Health in an email.
"I believe that daily use of broad-spectrum sunscreens with frequent reapplications may have more profound measurable effects on photoaging," she added. "But the key to prevention is to develop these healthy sun-protective habits at a young age."