Offering free sunscreen to people at public events might not be enough to motivate them to properly protect themselves from harmful rays, a recent experiment suggests.
Researchers set up complimentary sunscreen dispensers at 10 information booths at the Minnesota State Fair, which typically draws more than 1.7 million attendees each August.
About 17,000 people used the free sunscreen. The researchers observed 2,187 sunscreen users and found just 33 percent of them applied it to all sun-exposed areas of their skin.
"Unfortunately, for many people, sun protection is not a priority," said senior study author Dr. Ingrid Polcari of the University of Minnesota in Minneapolis.
"All exposed skin should be protected from the sun, either with clothes or with sunscreen," Polcari said by email.
When people at the fair didn't use enough sunscreen, about half of them covered their upper arms and roughly 42 percent applied it to their face, researchers report in the Journal of the American Academy of Dermatology. Very few of them applied sunscreen on their chest or legs.
Among people observed using at least some sunscreen, 38 percent didn't have any additional protection like a hat, sunglasses or long-sleeved clothing, the study also found.
Women did better than men: they made up 51 percent of people at the fair but accounted for 57 percent of sunscreen users at the free sunscreen stations.
Fairgoers were more likely to use sunscreen when it was sunnier outside than when it was cloudy, and sunscreen use declined dramatically on completely overcast days.
"Many people believe that sunscreen is only for when you are at the beach and that it's not needed as part of their everyday lives," said Dr. Elizabeth Martin, president of Pure Dermatology and Aesthetics in Hoover, Alabama.
"Many people also mistakenly believe that they do not need sunscreen on cloudy days, but even then, up to about 80 percent of the sun's harmful UV rays can reach the skin," Martin, who wasn't involved in the study, said by email.
One limitation of the study is that sunscreen habits in Minnesota might not necessarily reflect what people would do in places where the weather is generally warmer and sunnier. It also didn't look at individual characteristics that might influence whether people used sunscreen or how much they applied.
Most people need at least an ounce of sunscreen, or enough to fill a shot glass, to cover all the exposed parts of their body, according to the American Academy of Dermatology.
It should offer broad spectrum (UVA and UVB) protection and have a Sun Protection Factor (SPF) of 30 or higher, the AAD recommends. Sunscreen should be applied at least 15 minutes before going outdoors, and reapplied every two hours or after swimming or sweating even if it’s labeled as water resistant.
Even when people get it for free, they still may not use sunscreen correctly because it requires more effort than other types of giveaways, said Dr. David Leffell, chief of dermatological surgery and cutaneous oncology at Yale School of Medicine.
"If they were giving out free candy bars, makeup or pool noodles, I am sure everyone would take advantage," Leffell, who wasn't involved in the study, said by email. "The problem with free sunscreen is that it is one of those gifts that requires you to do something, like giving someone a pet as a birthday present."