A new study from UC San Francisco concludes that tanning beds cause non-melanoma skin cancer.

UCSF dermatologist Eleni Linos says she was surprised to find how many cases of non-melanoma skin cancer are caused by tanning beds: 170,000 a year in the United States.
 
"Theoretically, if we stopped using tanning beds altogether, these would be avoidable or preventable cases, and that's a big number," she said.

Scientists had already linked tanning beds with malignant melanoma, a rarer but deadlier form of cancer.    
The study, published in the British Medical Journal, says people who start using tanning beds before age 25 run a higher risk of developing skin cancer.     

Last year California passed a law prohibiting anyone under 18 from using tanning beds.