Indoor Tanning and the Risk of Overall and Early-Onset Melanoma and Non-Melanoma Skin Cancer: Systematic Review and Meta-Analysis.

The aim of this study was to examine the association between indoor tanning use and the risk of overall and early-onset (age < 50) melanoma and non-melanoma skin cancer (NMSC). To evaluate the association between indoor tanning and skin cancer, a systematic review of the literature published until July 2021 was performed using PubMed, EMBASE, and MEDLINE. Summary relative risk (RR) from 18 studies with 10,406 NMSC cases and 36 studies with 14,583 melanoma cases showed significant association between skin cancer and indoor tanning (melanoma, RR= 1.27, 95% CI 1.16-1.39; NMSC, RR = 1.40, 95% CI 1.18-1.65; squamous cell carcinoma (SCC), RR = 1.58, 95% CI 1.38-1.81; basal cell carcinoma (BCC), RR = 1.24, 95% CI 1.00-1.55). The risk was more pronounced in early-onset skin cancer (melanoma, RR = 1.75, 95% CI 1.14-2.69; NMSC, RR = 1.99, 95% CI 1.48-2.68; SCC, RR = 1.81, 95% CI 1.38-2.37; BCC, RR = 1.75, 95% CI 1.15-2.77). Moreover, first exposure at an early age (age ≤ 20 years) and higher exposure (annual frequency ≥ 10 times) to indoor tanning showed increasing risk for melanoma (RR = 1.47, 95% CI 1.16-1.85; RR = 1.52, 1.22-1.89) and NMSC (RR = 2.02, 95% CI 1.44-2.83; RR = 1.56, 95% CI 1.31-1.86). These findings provide evidence supporting primary prevention policies regulating modifiable behaviors to reduce the additional risk of skin cancer among younger adults.