Indoor tanning in businesses and homes and risk of melanoma and nonmelanoma skin cancer in 2 US case-control studies.

BACKGROUND Indoor tanning increases skin cancer risk. Beyond early research describing melanoma and sun lamps, few recent reports describe where individuals indoor tan and whether skin cancer risk varies by location (business, home-based). OBJECTIVE We sought to assess where individuals tanned indoors and skin cancer risk by tanning device location. METHODS Multivariate logistic regression was conducted in 2 US case-control studies of melanoma (1161 cases, 1083 controls, ages 25-59 years) and early-onset basal cell carcinoma (375 cases, 382 controls, age<40 years) conducted between 2004 and 2010. RESULTS Most indoor tanners (86.4%-95.1%), especially younger individuals, tanned exclusively in businesses. Persons who used indoor tanning exclusively in businesses were at increased risk of melanoma (odds ratio 1.82, 95% confidence interval 1.47-2.26) and basal cell carcinoma (odds ratio 1.69, 95% confidence interval 1.15-2.48) compared with non-users. Melanoma risk was also increased in the small number who reported tanning indoors only at home relative to non-users (odds ratio 4.14, 95% confidence interval 1.75-9.78); 67.6% used sun lamps. LIMITATIONS Self-reported tanning and potential recall bias are limitations. CONCLUSION Business-only tanning, despite claims of "safe" tanning, was positively associated with a significant risk of melanoma and basal cell carcinoma. Home tanning was uncommon and mostly from sun lamps, which were rarely used by younger participants. Regardless of location, indoor tanning was associated with increased risk of skin cancer.