No causal link between sunbed-use and cancer

This article appears at http://www.spiked-online.com/index.php/site/article/8659/

Wednesday 28 April 2010

Basham and Luik

Let’s put cancerous myths to bed
There’s no causal link between sunbed-use and cancer, so why are politicians clamping down on teens tannning?

Ever since the International Agency for Research on Cancer (IARC) concluded, last summer, that ultraviolet (UV) radiation exposure from sunbeds is ‘carcinogenic to humans’, the British medical and health promotion establishment, along with the government, has been ramping up efforts to ban the use of sunbeds. Now, Gillian Merron, Britain’s public health minister, has said that the government intends to ban under-18s from using tanning salons after a study in the British Medical Journal reported that at least 250,000 children aged 11 to 17 use sunbeds.

The basis for the IARC decision and the government’s intervention is twofold: first, that there is a melanoma epidemic in the UK, and, second, that there is a causal connection between sunbed-use and melanoma. Both of these claims are scientifically suspect.

In a recent study about the reported incidence of melanoma in the UK, a group of scientists at the dermatology department of Norfolk and Norwich University Hospital found that the increase in melanoma in East Anglia between 1991 and 2004 was ‘almost entirely due to minimal, stage 1 disease. There was no change in the combined incidence of the other stages of the disease, and the overall mortality only increased from 2.16 to 2.54 cases per 100,000 per year.’ According to the report authors, the claims of a melanoma epidemic are based not on a real increase in cases but rather on a ‘diagnostic drift which classifies benign lesions as stage 1 melanoma’. In the past these cases would have been diagnosed as benign melanocytic nevi, not melanoma.

Further weakening the claim that these early stage melanomas were the result of excessive sun exposure is the fact that most of the cases were in areas of the body not exposed to the sun. One of the report authors, Dr Nick J Levell, told Reuters, ‘The main message is to be cautious about overstating messages about a melanoma epidemic to the public and media. Such behaviour will tend to induce unnecessary anxiety and behaviour that may cause distress and harm.’

Yet the IARC claim about sunbeds and cancer risk does precisely what Levell warns against. In its press release announcing that it had concluded that radiation from sunbeds is carcinogenic, IARC implied that this finding was based on new scientific evidence. This was not the case. The basis for IARC’s conclusion is the agency’s 2006 report Exposure to Artificial UV Radiation and Skin Cancer. But this report provides no compelling evidence that sunbed-use is associated with an increased risk for skin cancer.



The report references 24 cohort and case-control studies on the association between use of indoor tanning facilities and melanoma risk. Of these only four show a small statistically significant relationship. None of the four have a relative risk greater than 1.50, indicating an extremely weak and unlikely relationship. Indeed, even the report authors admit that the evidence for a positive association between indoor tanning and melanoma is ‘weak’. It might be suggested that this statement is in itself misleading since the relationship is, in fact, practically nonexistent.

Despite the fact that there is virtually no scientific support in IARC’s report for the conclusion that ultraviolet radiation exposure from sunbeds is ‘carcinogenic to humans’, it is this very study that provides the sole basis for Gillian Merron’s move to ban adolescent use of tanning beds.

Finally, the largest prospective study of the risk of sunbeds for melanoma was by a team of researchers headed by Marit Veierød at the University of Oslo. They followed more than 100,000 Norwegian women over an average eight-year period and found no statistically significant association between sunbed-use and melanoma in those aged 10 to 19 who used a tanning facility more than once a month. Yet this is the target group for the UK government’s anti-sunbed campaign. Moreover, these findings correspond to a British study from 2004 which did not find a statistically significant association between use of sunbeds and melanoma.

So, not only is the public health minister failing, in the words of Levell, to be ‘cautious about overstating messages about a melanoma epidemic’ and tanning parlours - she has also proposed action that is clearly unsupported by the scientific evidence.

Patrick Basham directs the Democracy Institute and is a Cato Institute adjunct scholar. John Luik is a Democracy Institute senior fellow. They will be discussing the faux melanoma epidemic and other attacks on working-class culture on 29 April at the Institute of Economic Affairs. For more information about the event, click here.