Wednesday July 25 2012
Some sunbeds expose skin to 15 times more radiation than the midday sun
Young people who use sunbeds almost double their risk of developing the most deadly form of skin cancer, the Daily Mail reported today, while The Daily Telegraph said sunbeds “raised cancer risk by 20 per cent”.
The stories are based on a major review of studies that looked at the risk of malignant melanoma, the most serious type of skin cancer, associated with the use of sunbeds in western Europe. It found that sunbed users had a 20% higher risk of melanoma compared to those who had never used one.
The cancer risk increased with additional sunbed sessions and almost doubled when sunbed use began before the age of 35 (87% higher risk).
In Europe each year the authors estimate that 3,438 new cases of melanoma would be due to sunbed use. This is of significant concern, as melanoma can often be fatal. In 2010, there were 2,203 deaths due to melanoma in the UK. The researchers estimate that 100 deaths a year from melanoma in the UK are a direct result of sunbed use.
This is a well-conducted and wide-ranging piece of research that confirms the findings of previous studies and provides a powerful argument for avoiding the use of sunbeds, particularly by young people.
The researchers go as far as to recommend that legislation be introduced to ban the use of sunbeds (which are illegal for under 18s) for all adults, but this is unlikely to happen in the near future.
Still, as the Evening Standard helpfully points out, using fake tan is a much safer alternative.
Where did the story come from?
The study was carried out by researchers from the International Prevention Research Institute, France, and the European Institute of Oncology, Italy. There is no information in the paper about external funding.
The study was published in the peer-reviewed British Medical Journal.
The research was covered fairly in the newspapers.
What kind of research was this?
This was a systematic review and meta-analysis looking at the risk of malignant melanoma from sunbed use in western Europe, including any dose-response effect and estimating the number of deaths attributable to sunbed use.
Malignant melanoma is one of three different types of skin cancer (the other two are squamous cell and basal cell skin cancer). Of the three, melanoma is the most serious, and if not caught early can quickly spread to the lymph nodes and to other parts of the body. Though less common than the other types of skin cancer, melanoma is responsible for most of the deaths due to the disease. About 2,000 people in England and Wales die each year from melanoma. Squamous cell and basal cell skin cancer are slower growing types of skin cancer, and can usually be cured completely by surgical removal.
Ultraviolet light is the most strongly established risk factor for skin cancer. The authors say that sunbeds give out the same type of harmful radiation as sunlight – with the rays from some tanning units 10-15 times stronger than the midday sunlight on the Mediterranean Sea. Indoor tanning is known to trigger cancerous processes including DNA damage. They say that while a previous systematic review from 2006 indicated that early sunbed use is associated with an increased risk of melanoma, this review did not examine the 'dose-response relationship' – how much the risk increases with increasing use of sunbeds. The current systematic review is an update of the 2006 review, which aims to examine this question.
What did the research involve?
The researchers searched a number of literature databases for studies relating to sunbed use and skin cancer published in the last 30 years, up to May 2012. From this initial search they selected published case-control, cohort and cross-sectional studies. They excluded ecological studies, case reports, reviews and editorials. The researchers looked for observational studies examining risk of any of the three types of skin cancer, but the specific focus of their analyses was on melanoma.
Using standard protocols, they extracted the relevant data from each study on the use of indoor tanning appliances, how often they were used (from including 'never use' – no use at all; 'ever use' – any use at all; and 'high use'), along with estimates of the risk of melanoma. They also looked at the risk associated with first use of sunbeds before the age of 35.
The researchers used standard statistical techniques to pool the results of the studies and analyse the relationship between amount of sunbed use, sunbed use before 35, and the risk of melanoma. In their analyses they took into account the heterogeneity between studies – that is, differences in the results of different studies, which can occur when different studies have examined different populations, and had different designs and methods. Heterogeneity can affect the reliability of the overall pooled results in a systematic review. The researchers also carried out separate analyses only including certain types of studies (for example only looking at cohorts and case controls), and analyses that only included studies that had adjusted for potential confounding factors that could have an influence (such as skin sensitivity).
To translate their estimates of risk into actual numbers of cases of melanoma that might be caused by sunbed use, they extracted data on the incidence of melanoma in 18 European countries. They also identified seven surveys from eight of these countries on the use of sunbeds. The eight countries, which included the UK, represent 70% of all melanoma cases occurring in the 18 countries studied. Prevalence of sunbed use in the other 10 countries was determined from estimates for neighbouring countries.
What were the basic results?
The authors found 27 studies which met their criteria and had examined the risk of melanoma according to sunbed use. The main results were:
- Users of sunbeds had a 20% increased risk of melanoma compared to those who had never used a sunbed (relative risk 11.20, 95% confidence interval 1.08 to 1.34).
- The risk of melanoma increased by 1.8% (95% confidence interval 0% to 3.8%) for each additional session of sunbed use annually.
- An analysis of the 13 studies that gave results according to age of first use found that those who first used sunbeds before the age 35 had an almost doubled risk compared to those who had never used sunbeds (relative risk 1.87, 95% confidence interval 1.41 to 2.48).
- In Europe, an estimated 3,438 cases of melanoma could be attributable to sunbed use, most (2,341) occurring among women.
Separate analyses according to study type, and to studies that had adjusted for confounders, gave similar risk figures.
How did the researchers interpret the results?
The researchers say that their analysis confirms previous research that sunbed use is associated with an increased risk of malignant melanoma, particularly among young people. They also found that the more that sunbeds are used, the higher the risk. Melanoma and other skin cancers can be prevented by avoiding exposure to these devices, they argue, and tough action is needed to further restrict sunbed use, including the possibility of total prohibition, as has been implemented in Brazil.
This well-conducted, systematic review confirms findings from previous research that sunbed use is associated with an increased risk of malignant melanoma, the most serious form of skin cancer, with young people who use sunbeds thought to be at greater risk. Perhaps unsurprisingly, it also found that the more someone uses a sunbed, the higher their risk.
The type of studies included in this review cannot prove that sunbeds caused the skin cancers, however. The authors point out that sunbed users also tend to adopt 'unhealthy lifestyles' and there is a possibility that sunbed use is a marker for higher exposure to the sun. However, several of the studies included adjusted their results for possible sun exposure. The authors also point out that there is compelling evidence that sunbed use causes melanoma from an investigation of a melanoma 'epidemic' in Iceland, where sunny days are uncommon. Here the incidence of melanoma after 1990 increased sharply as use of sunbeds became more common, mainly in young women and often on the trunk. It tended to decline after 2000 when the authorities imposed greater controls on sunbeds.
Melanoma is a very serious form of skin cancer that can quickly spread to the lymph nodes and to other parts of the body if not caught early. Cancer Research UK currently reports that it is the fifth most common cancer in the UK, and accounted for 4% of all new cancer cases in 2010. There are around 20 new melanoma cases for every 100,000 males in the UK and around 21 for every 100,000 females. In 2010, 2,203 people in the UK died from melanoma. Ultraviolet light is well established as the main risk factor for melanoma. The Health and Safety Executive advises certain people never to use sunbeds, including those who have skin which burns easily, and those who have lots of moles.
Read more advice about using sunbeds.
Analysis by NHS Choices. Follow Behind the Headlines on twitter.