The survey, part of a study led by dermatologists at Washington University School of Medicine in St. Louis, also found that many tanning salon employees across the state said indoor tanning had no associated risks or would prevent future sunburns - both false claims, according to the study's authors.
Missouri is one of 17 states that has no minimum age restrictions on tanning bed use and does not require parental consent.
"This should serve as a wake-up call for parents in Missouri and other states that don't regulate tanning beds," says study co-author Lynn Cornelius, MD, chief of the Division of Dermatology and the Winfred A. and Emma R. Showman Professor in Dermatology at Washington University. "With the absence of logical age restrictions, we are failing to protect our children, who are at an increased risk of developing skin cancer when exposed to the high-intensity levels of ultraviolet light that can be received in a tanning bed."
The findings appear online Feb. 25 in Pediatrics
Exposure to ultraviolet light from tanning beds makes users 75 percent more likely to develop melanoma than nonusers, and some studies have reported an increased risk of up to three times, Cornelius says. They're also up to 2.5 times more likely to develop more common nonmelanoma skin cancers, such as basal cell and squamous cell cancers.
Of the states that regulate tanning bed use, some ban minors until they reach a certain age; others require parental permission. Last year California became the first state to prohibit the use of indoor tanning beds by anyone younger than 18.
Cornelius says she and her colleagues at the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine routinely see young, typically female, melanoma patients who report previous tanning bed use.
"Indoor tanning may seem innocuous at first," she says. "Due to what is called 'tumor lag time,' or the time between an exposure to a carcinogen such as ultraviolet and the development of a cancer, it may take a decade or longer for someone who has been exposed to artificial ultraviolet radiation from tanning beds to develop a skin cancer."
For the study, the researchers identified 831 indoor tanning facilities across Missouri and randomly selected and called 375 of them, posing as prospective clients. For consistency, the researchers made attempts to survey each salon twice.
Of the facilities called, 243 salons completed two interviews and were included in the analysis. Operators of 65 percent of the participating facilities said they would allow children as young as 10 or 12 to use indoor-tanning devices. Employees at 43 percent claimed there were no risks associated with indoor tanning, and 80 percent of facility operators said indoor tanning would prevent future sunburns. Both claims are false, the study notes.
The World Health Organization has stated that people younger than 18 should not use tanning beds, a recommendation based on several scientific studies. The International Agency for Research on Cancer has deemed ultraviolet rays from the sun and artificial tanning devices as carcinogenic to humans, equivalent to tobacco.
"Minimizing exposure to ultraviolet rays, no matter the source, lowers one's risk of skin cancer," says Graham Colditz, MD, PhD, a cancer prevention expert at Washington University and the Siteman Cancer Center who wasn't involved in the study. "The problem with indoor tanning is that users start very young and, unlike the sun, tanning beds are a completely avoidable cancer risk."
He recommends that people of all ages avoid ultraviolet rays from tanning beds and protect themselves as much as possible while in direct sunlight. Hats, long-sleeve shirts and the use of a broad-spectrum sunscreen with an SPF of 30 or higher are helpful, he says. And instead of tanning booths, Colditz recommends sunless tanning lotions, which have not been proven unsafe and pose no risk of inhalation, as might spray tans.
Here are other precautions for lowering cancer and other disease risks.