Currently, the rate of melanoma, a deadly form of skin cancer, is on the rise in the United States. In addition, the rate is increasing more rapidly among women than men younger than 50 years. A new study was based on the premise that this difference was related to the greater use of indoor tanning by younger women. In 2009, indoor tanning was classified as a human carcinogen by the World Health Organization (WHO). The findings were published online on January 27 in the journal JAMA Dermatology.
The study authors note that to the best of their knowledge, no study has looked at age- and sex-specific associations between indoor tanning and melanoma to determine whether these trends could be due to greater indoor tanning use among younger women. Therefore, they conducted a study to examine associations between indoor tanning and melanoma among men and women younger than 50 years.
The study group comprised 681 patients (465 [68.3%] women) who were diagnosed with melanoma from 2004 and 2007, and 654 controls (446 [68.2%] women), aged 25 to 49 years. Indoor tanning was defined as any use, first age of use, and total sessions. Gender-specific associations for indoor tanning and melanoma by anatomic site were examined.
The investigators found that, compared to women aged 40 to 49 years, women younger than 40 years began indoor tanning sessions at a younger age (16 vs. 25 years) and reported more frequent indoor tanning (average number of sessions: 100 vs. 40). Women younger than 30 years of age were six times more likely to be in the case than the control group if they tanned indoors. In addition, melanoma rates were significantly elevated among women, ages 30 to 49 years; a dose response was observed among women regardless of age. Among men, results by age were inconsistent. The strongest melanoma risk for indoor tanning by anatomic site was for melanomas arising on the trunk of women.
The authors concluded that indoor tanning is a likely factor for the steeper increase in melanoma rates in the US among younger women compared with men, given the timing of when women began using indoor tanning relative to diagnosis. They stressed that the melanoma epidemic can be expected to continue unless indoor tanning is restricted and reduced.
The authors are affiliated with: Masonic Cancer Center, University of Minnesota, Minneapolis; Division of Epidemiology and Community Health, University of Minnesota, Minneapolis; Center for Dermatoepidemiology, VA Medical Center, Providence, Rhode Island; Department of Dermatology, Rhode Island Hospital, Providence; Department of Dermatology and Epidemiology, Brown University, Providence, Rhode Island; Department of Dermatology, University of Minnesota, Minneapolis; Department of Internal Medicine, University of New Mexico Cancer Center, Albuquerque; and Division of Epidemiology and Biostatistics, University of New Mexico, Albuquerque.