Indoor tanning linked to high skin cancer risk in US and abroad

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1. Approximately 1 in every 5 adolescents worldwide and >55% of American university students have been exposed to indoor tanning.                                                                       

2. Over 460,000 cases of malignant melanomas (MM) and non-melanoma skin cancer (NMSC) can be attributed to indoor tanning in the United States, Canada, Northern and Western Europe, and Australia. This is greater than the number of lung cancer cases attributed to smoking in the same geographical region. 

Evidence Rating Level: 1 (Excellent)

Study Rundown: Indoor tanning is a known carcinogen associated with both MM and NMSC; its deleterious effects are exacerbated at young ages. This study was the first attempt to ascertain international prevalence of indoor tanning.  The results indicated high prevalence of ever-exposure to indoor tanning amongst all age groups with the highest prevalence in university students. The study also demonstrated tremendous associated health-burden in relation to MM and NMSC, thereby highlighting the need for public health intervention, especially in younger age groups. This study’s strengths include the meta-analyses design, consisting of analysis of a large pool of participants with stringent inclusion-exclusion criteria. The study was limited by its homogeneous population, which mainly consisted of Caucasians from Western countries, thereby limiting worldwide applicability.

Click to read the study in JAMA Dermatology

Relevant Reading: Use of Indoor Tanning Sunlamps by US Youth, Ages 11-18 Years, and by Their Parent or Guardian Caregivers: Prevalence and Correlates

In-Depth [meta-analysis]: Authors selected 88 studies for the primary analysis obtained from PubMed, Scopus, Web of Science, and publicly available data that had not yet been published. This included 405,696 participants from the United States, Canada, Northern and Western Europe, and Australia that were stratified into 3 age groups: (1) adults ≥ 18 years old, (2) university students (undergraduate or graduate school) (3) adolescents ≤19 years old. Random-effects model meta-analyses were utilized to calculate the prevalence of indoor tanning in the three age groups. Using calculated population proportional attributable risk and the 95% confidence intervals of published estimates of incidences of Basal and Squamous cell carcinoma and melanomas, the authors estimated the number of skin cancer cases that can be attributed to indoor tanning. Prevalence of ever-exposure to indoor tanning was 35.7% for adults (95% CI, 27.5-44.0%), 55% for university students (95% CI, 33.0%-77.1%), and 19.3% for adolescents (95% CI, 14.7%-24.0%). 452,796 cases of NMSC and 11,374 of MM were attributed to indoor tanning. To demonstrate the clear healthcare burden, authors compared this value, which was found to be greater than the 362,941 cases of lung cancer attributed to smoking within the same region. Furthermore, because of the high prevalence of youth exposure to indoor tanning, these numbers do not yet capture the presumed increased risk as this exposed-generation ages.

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