More evidence of harms of sunbed use, particularly for young peopleBMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e6101 (Published 02 October 2012) Cite this as: BMJ 2012;345:e6101
- Catherine M Olsen, senior research officer 1,
- Adèle C Green, head, cancer and population studies group 1
Exposure to ultraviolet radiation, either from the sun or from artificial sources, causes skin cancer.1 Tanning beds have emerged as a prevalent but preventable source of such exposure. Over the past two decades, acquiring a tan through exposure to artificial sources of ultraviolet radiation has become popular among fair skinned people, particularly adolescents and young adults.2 3 4 The use of such tanning devices has been associated with a significantly increased risk of melanoma. Two linked research papers provide further evidence of the harmful effects of indoor tanning.5 6
What is already known about the risks of indoor tanning? A meta-analysis conducted by the International Agency for Research on Cancer (IARC) working group on artificial ultraviolet light and skin cancer,7 which used data from 19 studies, reported a modest increase in the risk of melanoma for “ever” compared with “never” exposure to indoor tanning equipment. It also found a higher pooled estimate if first exposure occurred before age 35 years. The IARC review also reported a twofold increased risk of developing cutaneous squamous cell carcinoma in sunbed users, although no association with basal cell carcinoma was found. These findings prompted the World Health Organization to classify tanning beds as a group 1 carcinogen,8 alongside tobacco smoking and asbestos.
Boniol and colleagues (doi:10.1136/bmj.e4757) present an updated meta-analysis of the association between the use of artificial tanning devices and melanoma.5 This review includes seven new studies (one cohort study, five population based case-control studies, and one cross sectional study) and an update from the Norwegian-Swedish Women’s Lifestyle and Health Cohort study, in total constituting an extra 3817 cases of melanoma (the earlier IARC review included 7355 melanoma cases). This review confirms the significant association with melanoma for ever use and for first exposure before age 35 years. In addition, the association remained significant when the analysis was restricted to studies that had adjusted for confounders related to sun exposure and sun sensitivity. Calculations for a dose-response association showed a 1.8% (95% confidence interval 0% to 3.8%) increase in risk of melanoma for each additional session of sunbed use per year. Although most included studies were conducted in the Northern hemisphere, two studies were conducted in Australia, and there was no significant variation in the pooled estimates by latitude. The authors estimated that 5.4% of melanoma cases (3438 cases each year) in western Europe could potentially be prevented by avoiding exposure to indoor tanning.
Wehner and colleagues’ meta-analysis (doi:10.1136/bmj.e5909) focuses on the risks of acquiring the more common keratinocyte skin cancers—basal cell carcinoma and squamous cell carcinoma—associated with indoor tanning.6 They analysed data from 12 studies (10 case-control studies, one nested case-control study, and one cohort study), with 7645 cases of basal cell carcinoma and 1683 cases of squamous cell carcinoma. The association between indoor tanning and the risk of these cancers has received less attention than that with melanoma. This is presumably because these cancers are not usually registered, are less aggressive, and have lower mortality, although squamous cell carcinoma does have metastatic potential. However, the morbidity associated with the treatment of these two types of skin cancer—surgical and otherwise—along with the avoidable costs to healthcare systems to treat them, are substantial.9
The pooled findings of this second updated meta-analysis showed a significant positive association between indoor tanning and the development of basal cell carcinoma (ever use pooled relative risk 1.29), with some evidence of a dose-response association (high dose pooled relative risk 1.50). The increased risk of squamous cell carcinoma and the higher risks of both cancers associated with exposure in early life (in this case before age 25 years) were confirmed; sensitivity analyses by study features, including adjustment for important confounders, did not materially alter the results. It is still unclear whether a dose-response association exists for squamous cell carcinoma. More data, ideally from prospective studies, are needed.
The additional findings of these two new reviews provide more convincing evidence that exposure to artificial ultraviolet radiation is a cause of the three main skin cancers. Importantly, there is now evidence from prospective cohort studies to support an increased risk for each cancer type.10
Some have postulated that indoor tanning has positive health benefits that should be taken into account, including the generation of vitamin D, although conclusive evidence of a benefit for vitamin D that is unrelated to bone health is not yet available.11 Thus, the known risks of skin cancer from indoor tanning currently outweigh its potential benefits. Many countries have enacted legislation to tighten regulations on the sunbed industry during the past decade. A total ban is in place in Brazil, and legislation prohibits use by people under 18 years in France; Spain; Portugal; Germany; Austria; Belgium; the United Kingdom; and parts of Australia, Canada, and the United States.12 These regulations must be tethered to warnings by health professionals and educators about the risks of indoor tanning. Young people in particular should be made aware that the use of sunbeds for short term cosmetic tanning carries the long term price of an increased risk of skin cancer.
Cite this as: BMJ 2012;345:e6101
Competing interests: Both authors have completed the ICMJE uniform disclosure 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; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Commissioned; not externally peer reviewed.