Researchers confirmed an association between tanning bed（日光浴床） use and an increased risk for three common skin cancers -- basal cell carcinoma, squamous（鳞状的） cell carcinoma and melanoma, according to results presented at the 10th AACR International Conference on Frontiers in Cancer Prevention Research, held Oct. 22-25, 2011. The popularity of indoor tanning is widespread, with roughly 10 percent of Americans using a tanning facility each year. However, use of tanning beds has been shown to be associated with an increased risk for skin cancer, according to lead researcher Mingfeng Zhang, M.D., research fellow in the department of dermatology（皮肤病学） at Brigham and Women's Hospital and Harvard Medical School in Boston.

For this cohort study, Zhang and colleagues followed 73,494 nurses who participated in the Nurses' Health Study II from 1989 to 2009. They tracked tanning bed use during high school and college and when women were aged between 25 and 35 years old. They also tracked the overall average usage during both periods in relation to basal cell carcinoma, squamous cell carcinoma and melanoma.

Results showed that tanning bed use increased skin cancer risk with a dose-response effect. More tanning bed exposure led to higher risks. Compared with nonusers, the risk for basal cell carcinoma and squamous cell carcinoma increased by 15 percent for every four visits made to a tanning booth per year; the risk for melanoma increased by 11 percent.

"The use during high school/college had a stronger effect on the increased risk for basal cell carcinoma compared with use during ages 25 to 35," Zhang said.

"These results have a public health impact on skin cancer prevention for all three types of skin cancer," she said. "[They] can be used to warn the public against future use of tanning beds and to promote restrictions on the indoor tanning industry by policymakers."

In follow-up studies, the researchers plan to monitor skin cancer incidence and to assess the association with tanning bed usage in this cohort during a longer term.