Information sourced from NEJM Journal Watch:
The Dark Side of Indoor Tanning to Prevent Outdoor Sunburns
Why our patients should take a dim view of this notion
Many studies have found an association between tanning bed exposure and increased risk for melanoma, but users often cite the desire to acquire a “base tan” to decrease the likelihood of sunburn on subsequent sun exposure and prevent skin cancer. If this reasoning is valid, indoor tanners who have not had sunburns would have a reduced melanoma rate. Investigators compared melanoma incidence in 1857 indoor tanners and never–indoor tanners (controls) stratified by the number of outdoor sunburns; those who had had sunbed-induced burns were excluded.
Indoor tanners had increased melanoma risk compared to controls regardless of sunburn history (adjusted odds ratio, 3.87; 95% confidence interval, 1.68–8.91; P=0.02), even after adjustments were made for variables including outdoor activity, eye and hair color, freckles, moles, and family melanoma history. Among individuals who reported no lifetime sunburns, indoor tanners were almost four times more likely than controls to have a melanoma diagnosis after adjustment for potential confounders (OR, 3.87; 95% CI, 1.68–8.91; P=0.002). Among subjects who reported more than 5 lifetime sunburns, indoor tanners were at greater risk for melanoma than controls (adjusted OR, 1.42; 95% CI, 1.19–1.69). Among indoor tanners who had melanoma, those who had had no sunburns started tanning at an earlier age, had more tanning sessions, and had the greatest number of years of indoor tanning.
Acquisition of a prevacation base tan to prevent sunburn is a frequent rationale for indoor tanning given by users and salon owners. These findings refute this idea. In fact, the indoor tanners with the fewest outdoor sunburns had the greatest risk for melanoma. Earlier research showed that ultraviolet A radiation (UVA) afforded no protection against cyclobutane pyrimidine dimers produced during subsequent UVA and UVB radiation exposure (NEJM JW Dermatol Jan 7 2011). Our patients should take a dim view of the notion that indoor tanning devices protect against melanoma.
Craig A. Elmets, MD reviewing Vogel RI et al. J Natl Cancer Inst 2014 May 28.