Indoor tanning and non-melanoma skin cancer: systematic review and meta-analysisBMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e5909 (Published 02 October 2012) Cite this as: BMJ 2012;345:e5909
- Mackenzie R Wehner, medical student1, MPhil scholar in epidemiology2,
- Melissa L Shive, medical student3,
- Mary-Margaret Chren, professor4,
- Jiali Han, associate professor56,
- Abrar A Qureshi, associate professor5,
- Eleni Linos, assistant professor4
- 1Stanford University School of Medicine, Stanford, CA, USA
- 2Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- 3University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- 4Department of Dermatology, University of California San Francisco (UCSF), 2340 Sutter Street, San Francisco, CA, 94143-0808, USA
- 5Department of Dermatology, Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- 6Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
- Correspondence to: E Linos
- Accepted 28 August 2012
Objective To synthesise the literature on indoor tanning and non-melanoma skin cancer.
Design Systematic review and meta-analysis.
Data sources PubMed (1966 to present), Embase (1974 to present), and Web of Science (1898 to present).
Study selection All articles that reported an original effect statistic for indoor tanning and non-melanoma skin cancer were included. Articles that presented no data, such as review articles and editorials, were excluded, as were articles in languages other than English.
Data extraction Two investigators independently extracted data. Random effects meta-analysis was used to summarise the relative risk of ever use versus never use of indoor tanning. Dose-response effects and exposure to indoor tanning during early life were also examined. The population attributable risk fraction for the United States population was calculated.
Results 12 studies with 9328 cases of non-melanoma skin cancer were included. Among people who reported ever using indoor tanning compared with those who never used indoor tanning, the summary relative risk for squamous cell carcinoma was 1.67 (95% confidence interval 1.29 to 2.17) and that for basal cell carcinoma was 1.29 (1.08 to 1.53). No significant heterogeneity existed between studies. The population attributable risk fraction for the United States was estimated to be 8.2% for squamous cell carcinoma and 3.7% for basal cell carcinoma. This corresponds to more than 170 000 cases of non-melanoma skin cancer each year attributable to indoor tanning. On the basis of data from three studies, use of indoor tanning before age 25 was more strongly associated with both squamous cell carcinoma (relative risk 2.02, 0.70 to 5.86) and basal cell carcinoma (1.40, 1.29 to 1.52).
Conclusions Indoor tanning is associated with a significantly increased risk of both basal and squamous cell skin cancer. The risk is higher with use in early life (<25 years). This modifiable risk factor may account for hundreds of thousands of cases of non-melanoma skin cancer each year in the United States alone and many more worldwide. These findings contribute to the growing body of evidence on the harms of indoor tanning and support public health campaigns and regulation to reduce exposure to this carcinogen.
We thank Stephen Bent of the University of California San Francisco and Emanuele Di Angelantonio of the University of Cambridge for their assistance.
Contributors: MRW, M-MC, and EL were involved in the conception and design of the study. MRW, MLS, and EL did the data collection and analysis. MRW, MLS, M-MC, and EL interpreted the data. MRW and EL drafted the manuscript, and all authors critically revised it for important intellectual content. All authors approved the final version to be published. EL is the guarantor.
Funding: This project was supported by award number KL2RR024130 from the National Center for Research Resources of the National Institutes of Health, and by award number K24 AR052667 from the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health. The study sponsors were not involved in the study design and the collection, analysis, and interpretation of data, nor the writing of the article or the decision to submit it for publication. The authors were independent from the study sponsors.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; MMC does consultancy for Genentech; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Not needed.
Data sharing: No additional data available.
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