European researchers set out to look for any relationship between use of tanning beds and skin cancer.
In this week's issue of the British Medical Journal, they concluded a review of 27 studies on the topic published between 1981 and 2012.
Mathieu Boniol of the International Prevention Research Institute and his co-authors estimated that of the 63,942 cases of melanoma diagnosed every year in 18 Western European countries, about 3, 438 cases of melanoma and 784 related deaths could be attributed to bronzing with tanning beds.
"The risk of cutaneous melanoma is increased by 20 per cent for those who were ever users of indoor tanning devices with artificial ultraviolet light," the study's authors concluded. "The risk of melanoma was doubled when use started before the age of 35 years."
The researchers believe that earlier studies tended to underestimate the risks of indoor tanning because use of the the devices is relatively new.
They said figures from Iceland, where sunny days are relatively uncommon, suggested that the incidence of skin cancer increased sharply in young females after 1990, then decreased in 2000 when authorities imposed stricter controls on tanning beds.
"Prevention of the harmful effects associated with sunbed use must be based on tougher actions," they concluded.
Restrictions for minors
Boniol's team called for restrictions on tanning by people under the age of 18 and bans on unsupervised tanning salons.
Last month, a CBC News test of tanning salons across Canada shows people under 18 are being allowed to tan without their parents' consent, contrary to voluntary industry guidelines.
In a response at the time, Steven Gilroy, executive director of the Joint Canadian Tanning Association, said his members welcome professional standards on who can use tanning beds.
Nova Scotia has had legislation prohibiting anyone under the age of 19 from using tanning beds since May 31, 2011. Quebec passed a ban for those under the age of 18 last month and other provinces have proposed similar legislation.
Australia and several European countries have implemented restrictions on tanning bed use by teens. California issued a ban for people under the age of 18 last October, the researchers said.
"If sunbed use by teenagers and young adults does not substantially decrease in the short term, then more radical actions should be envisioned, such as the nationwide prohibition of the public use of tanning devices, which was implemented by the Brazilian National Health Surveillance Agency84 in November 2009," the researchers suggested.
Health Canada's voluntary guidelines for tanning salon operators recommend they assess factors such as a client's ability to tan, the client's history of sunburn and the use of any medication that could react with UV radiation. Those guidelines note that children under 16 should not use tanning equipment.
An estimated 5,800 Canadians will learn they have melanoma this year, according to Canadian Cancer Statistics 2012, published by the Canadian Cancer Society.