Do UV Tanning Beds Really Prolong Lifespan?

According to a recent article in the Daily Telegraph, the leading conservative newspaper in the UK, research from the University of Edinburgh shows that using ultraviolet sunbeds could prolong your life.

How could a normally responsible newspaper make such a bizarre claim about research from a leading British university? Let’s examine what happened.

The flawed article

The Daily Telegraph article reports on a recent scientific paper published by researchers from the University of Edinburgh. The paper concludes that outdoor exposure to higher levels of natural ultraviolet light in sunlight, and the use of indoor ultraviolet tanning beds, are associated with reduced mortality from heart disease and cancer.

The fundamental flaw in this conclusion is that sunlight is comprised of a broad spectrum of light, including invisible ultraviolet, all the spectral color wavelengths of visible light, and invisible infrared light. Sun-seeking behaviors such as spending more time outdoors, or living in lower latitudes, increase exposure to all of these spectral wavelengths, not just ultraviolet light.

So, to claim these effects are due specifically to the exposure to the ultraviolet short wavelengths in sunlight is overreaching. The authors could have just as easily concluded that the effects were due to green or orange wavelengths, which are also increased in intensity in people with sun-seeking behaviors.

How can the reported reduced cancer and heart disease mortality in indoor tanning bed users be explained? Does that indicate, as the authors suggest, that the ultraviolet component of the solar spectrum is responsible for the increased lifespan?

There is another, much more likely, explanation. It is well established that ultraviolet tanning bed users are also the most active sunseekers. They spend more time outdoors in sunlight, have more outdoor hobbies, and suffer more sunburns than people who never use tanning beds. So, in other words, these sunbed users are more exposed to all the visible and non-visible wavelengths in sunlight—and not just ultraviolet light.

In a previous preprint of this article the authors reported:

Participants with more active sun-seeking behaviour were at a lower risk of all-cause mortality, cardiovascular disease mortality, and cancer mortality compared to participants with less active sun-seeking behaviours, adjusted for demographic, socioeconomic, behavioural and clinical confounders

In other words, sun-seeking—i.e., spending more time outdoors—is the key determinant of good health and longevity.

Daylight exposure does improve health and lengthen lifespan

In my book, The Light Doctor, I discuss the extensive evidence that exposure to outdoor daylight is associated with reduced rates of cardiovascular disease and cancer deaths and contributes to extended life spans compared to people who spend most of their time indoors. A significant contributor to increased health and lifespan is the sky-blue wavelengths (440-495 nm) in daylight, which robustly synchronize our circadian clocks and optimize our health. With these circadian blue wavelengths, we have a well-established causal pathway—something that is lacking with ultraviolet light.

Previously on this page, we have discussed much about the science of healthy lighting, drawing on a research literature of over 10,000 peer-reviewed scientific articles (i.e., scrutinized before publication by expert, qualified scientists). I have also led a Consensus Study of 248 leading circadian scientists who have assessed and evaluated the research findings and conclusions in context based on over 40 years of research and investigation in this field. In other words, you get the benefit of my and my scientific colleagues judgement and experience in my book and on this blog.

New studies are published constantly, as research is very active in the healthy lighting field. But it is dangerous for journalists to uncritically report on these individual isolated scientific articles, and as a result, confuse, mislead or alarm the general public.

UV Tanning beds are harmful to your health

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In case you have any doubt, contrary to the assertions of the Daily Telegraph and the University of Edinburgh, the overall medical research evidence indicates that the use of UV tanning beds is harmful to your health. The risk of skin cancers, including malignant melanomas, is substantially increased, and your immune system can be impaired. As a result, the International Agency for Research on Cancer of the World Health Organization (WHO) officially classified indoor tanning as a human carcinogen in 2009.