Sunbed users are more than twice as likely to develop skin cancer, and the young are at extra risk, scientists in the US have warned.

In the Journal of the National Cancer Institute the researchers report on interviews with 1,500 people in New Hampshire, aged 25 to 74, covering exposure to the sun or sunlamps, smoking, tendency to sunburn and radiation treatment. The group included more than 800 newly diagnosed with skin cancers and 540 free of the disease.

Those using tanning lamps were 2.5 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop basal cell carcinoma, the survey found.

Margaret Karagas, of Dartmouth medical school, said: "Tanning lamps mimic sunlight [with] an intense, concentrated dose of ultraviolet radiation. We'd predict people using [them] may get cancers."

Lamp users often got a burn like sunburn, which is linked to cancers. Dr Karagas said the younger the lamp user the greater the risk; sun exposure early in life played a role in cancer risk.

"There is no such thing as a safe tan," said a spokesperson for Cancer Research UK. "A tan is actually the body's response to DNA damage."