Tanning beds: What do the numbers really mean?

May. 7th, 2010 by Pia Christensen
Filed under: Health data, Health journalism, Studies 

This is a guest post from Ivan Oransky, M.D., editor of Reuters Health and AHCJ’s treasurer, has written at my invitation.

May has been declared “Melanoma Awareness Month” or “Skin Cancer Awareness Month“ – depending on which group is pitching you – and reporters are doubtlessly receiving press releases and announcements from a number of groups, including the Melanoma Research Foundation, the Skin Cancer Foundation, hospitals, doctors and other organizations.

Those press releases often point to the World Health Organization, which reports that “use of sunbeds before the age of 35 is associated with a 75% increase in the risk of melanoma” – a statistic often repeated in news stories about tanning beds.

tanning-bed

Photo by Whatsername? via Flickr

But what does that really mean? Is it 75 percent greater than an already-high risk, or a tiny one? If you read the FDA’s “Indoor Tanning: The Risks of Ultraviolet Rays,” or a number of other documents from the WHO and skin cancer foundations, you won’t find your actual risk.

That led AHCJ member Hiran Ratnayake to look into the issue in March for The (Wilmington, Del.) News Journal, after Delaware passed laws limiting teens’ access to tanning salons. The 75 percent figure is based on a review of a number of studies, Ratnayake learned. The strongest such study was one that followed more than 100,000 women over eight years.

But as Ratnayake noted, that study “found that less than three-tenths of 1 percent who tanned frequently developed melanoma while less than two-tenths of 1 percent who didn’t tan developed melanoma.” That’s actually about a 55 percent increase, but when the study was pooled with others, the average was a 75 percent increase. In other words, even if the risk of melanoma was 75 percent greater than two-tenths of one percent, rather than 55 percent greater, it would still be far below one percent.

For some perspective on those numbers, Ratnayake interviewed Lisa Schwartz, M.D.,M.S., whose work on statistical problems in studies and media reports is probably familiar to many AHCJ members. “Melanoma is pretty rare and almost all the time, the way to make it look scarier is to present the relative change, the 75 percent increase, rather than to point out that it is still really rare,” Schwartz, a general internist at Veterans Affairs Medical Center in White River Junction, Vt., told him.

In a nutshell, the difference between skin doctors’ point of view and Schwartz’s is the difference between relative risk and absolute risk. Absolute risk just tells you the chance of something happening, while relative risk tells you how that risk compares to another risk, as a ratio. If a risk doubles, for example, that’s a relative risk of 2, or 200 percent. If it halves, it’s .5, or 50 percent. Generally, when you’re dealing with small absolute risks, as we are with melanoma, the relative risk differences will seem much greater than the absolute risk differences. You can see how if someone is lobbying to ban something – or, in the case of a new drug, trying to show a dramatic effect –  they would probably want to use the relative risk.

This is not an argument for or against tanning beds. It’s an argument for clear explanations of the data behind policy decisions. For some people, the cosmetic benefits of tanning beds – and the benefit of vitamin D, for which there are, of course, other sources – might be worth a tiny increase in the risk of melanoma. For others, any increased risk of skin cancer is unacceptable. (And of course, for the tanning industry, the benefits can be measured in other ways – dollars.) But if reporters leave things at “a 75 percent increase,” you’re not giving your readers the most important information they need to judge for themselves.

So when you read a study that says something doubles the risk of some terrible disease, ask: Doubles from what to what?

Related

These numbers also might come up in reporting about the health reform bill as it does in “Indoor Tanning Getting Moment in the Sun” (March 26, 2010). From the story:

Over the past decade, indoor tanning has increasingly been likened to other maligned habits, cigarette smoking in particular.

And with the passage of the new health care bill, government officials are prepared to take that comparison one step further. A 10 percent tax could be levied on indoor tanning as early as July, in an effort to offset some of the health care bill’s multi-billion-dollar budget.

AHCJ resources on writing about medical studies:

In addition, look for a slim guide about covering medical studies that AHCJ will publish this summer.

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Comments

27 Comments on Tanning beds: What do the numbers really mean?

  1. Ed on Fri, 7th May 2010 8:28 PM

    2. I could not agree more. 75% of nothing is still nothing.
    Can someone please tell me what the goal of the politicians and American Academy of Dermatology is?

  2. Steve Scott on Sat, 8th May 2010 6:25 PM

    3. The goals of the politicians is simply to fund the huge cost of the health care bill in such a way as to create a new tax that will go largely unnoticed or fought. The tan tax is being levied upon a group (mom & pop independent businesses) that lack the power and money to fight it. Remember, it was put in place to placate the AMA/dermatologists/cosmetic surgeons who used their hugely influential (read monied) lobbyists to kill the ‘botax’, which was in the original bill as a tax on elective cosmetic surgery procedures. That tax was at least less impactful because the people who would pay it are typically wealthy, high net worth females.

    Dermatologists, on the other hand, have pulled off a brilliant marketing coup for the last ten years that has been wildly profitable for their businesses. By waging the ’sunscare campaign’ that we are hammered with almost daily by media outlets around the world, every time someone gets a minor lesion of any type on their skin, they rush to the dermatologist to make sure it isn’t skin cancer. The derm immediately recommends a biopsy and, $750 later, prescribes an overpriced ointment, or better yet, a skin care regimen using exclusively formulated products only available through his office. Plus a series of follow up exams because “You should be checked over at least once a year for any possible changes on your skin.” (Just heard that one last week from CBS’s morning show doctor.)

  3. Cris Moffitt on Mon, 10th May 2010 9:32 AM

    4. Great article! Thanks for true objectivity and clear/straight talk, which is greatly lacking in typical discussion on this topic. :-)

  4. Dr. Gayle on Tue, 11th May 2010 4:36 PM

    5. I speak often on the issues in rural America and problems accessing health as well as provision of health with a focus on current health practices.

    Mainstream health journalists do little to look at too much more than what is fed into the pipeline. There is such little understanding of the science behind natural health and to broaden your perspectives would go a long way in taking the bias out of so-called “health reporting”.

  5. Mera on Wed, 12th May 2010 4:45 PM

    6. All I know is that people who go to tanning beds ALWAYS look like baked potatoes by the time they’re 45. Always! They think they look tanned and “healthy”, but it really looks awful. That’s enough of a reason for me to stay out of them.

  6. Faye on Thu, 13th May 2010 9:17 AM

    7. Great article- really clears up the misconception that any use of a tanning bed will surely leave you developing skin cancer! Everything we do in life has some sort of risk associated with it. Everything we do should be done in moderation, including the use of tanning beds. Hopefully people will get a hold of this article and it will shed some light on the ridiculous “75% increase” misnomer.

  7. sarah on Thu, 13th May 2010 9:47 AM

    8. Mera - “baked potatoes” are over exposed to UV rays. If you tan smart and do not over-expose you will only reap the excellent benefits the “sun” has to offer.

  8. Chad on Thu, 13th May 2010 12:59 PM

    9. Great article!! Thanks for printing the truth.

  9. Kristy on Thu, 13th May 2010 1:19 PM

    10. Mera- Always? So I’m assuming you know everyone who tans indoors then? Your point seems a little off because the people who practice smart tanning and don’t over do it (ie the ones that never make the headlines because they are the real examples of smart tanning and don’t produce a story to bash) don’t look like “baked potatoes”. Your simply following the lead of everyone else and just assuming that everyone who tans over does it, and that my dear is completely false. Please educate yourself on both aspects and sides before judging.

  10. Len Bickford on Thu, 13th May 2010 2:09 PM

    11. Great job! And it would make sense that people who use tanning beds enjoy being in the sun, justifying the one tenth of one percent increase. Unfortunately good news doesn’t make headlines enough! It is, and always will be, about the money. Where are the Headlines that read “Cancer causing Sunscreen Banned! Due to epidemics of disease and death!” The truth means nothing. How long have we lived on this planet? Lets look back a measly 100 years for a minute…..
    Only 14 percent of the homes had a bathtub.
    Only 8 percent of the homes had a telephone.
    There were only 8,000 cars and only
    144 miles of paved roads.
    More than 95 percent of all births took place at HOME.
    Ninety percent of all doctors had
    NO COLLEGE EDUCATION!
    Instead, they attended so-called medical schools, many of which
    Were condemned in the press AND the government as ’substandard. ‘
    And YES we went outside without sunscreen. And we flourished. And our Kids played outside, and helped around the house. And walked to school!
    I could go on and on, but what’s the point.
    Thank you for the article, it should put things into perspective for the few who read it.

  11. Steph on Thu, 13th May 2010 3:16 PM

    12. Receiving UV light is a natural process to our bodies when we step outside, even if its cloudy. So for those who practice Smart Tanning have already been proved that tanning has benefits to our bodies. Now over exposure is a different story, that’s where people look like ” baked potatoes” and are unhealthy looking, but this is a great article. Educating our selves is also a great component to smart tanning!! Keep the articles coming! :)

  12. Alison on Thu, 13th May 2010 6:08 PM

    13. From someone who works in the tanning industry, I can say that I appreciate the other perspective. I’d also like statistics of the likelihood of other diseases paired with the melanoma statistics. Vitamin D, plentiful in tanner’s bodies, prevents other cancers and osteoporosis. If you are slightly more likely to get melanoma, but slightly less likely to get other cancers, these risks should even out. The tan tax is going to come at a time when small business does not need a hit. This is especially obsurd in a state that highly regulates tanning, North Carolina, and for a salon that has a no burn policy, truly taking care of our customers’ skin. I’d like this perspective to be publicized more, so people can decide the truth for themselves.

  13. Gord T. from Canada on Thu, 13th May 2010 11:08 PM

    14. Good report. Still, cancer aside, doesn’t ANY tanning indicate cell damage that will lead to premature aging of the skin? It’s ironic to see the young with their good skin wanting to tan so much. Why? We should stay out of the salons AND out of the direct sun.

  14. Bruce W. on Fri, 14th May 2010 3:21 PM

    15. Gord T >
    Tanning is actually your bodies Defense AGAINST damage to the cellular structure. Like everything else, moderation is the key. Overexposure to UV is similar to overdoing in the weight room, or drinking a gallon of wine a day vs. a single glass.

    Here’s a story just today from your neck of the woods up North from a local MD. http://xr.com/CanTbed

    “Human beings evolved under ultraviolet light. This is the way our bodies were biologically designed to produce vitamin D and it is a mistake to ignore this.”

    “The health implications of vitamin D deficiency caused by anti sun messaging have put our health at risk”

    “The truth is that the benefits of ultraviolet light have been underestimated while its dangers have been grossly exaggerated”

    “Dr. Rona recommends Canadians consider using a sunbed that emits UVB light during the winter months to maintain healthy vitamin D blood levels”

    Sunbeds are an alternative source of controlled and moderate exposure in a non-burning fashion on a regular basis. Many skin types would require a half session or so to keep Vitamin D levels double the National Average.

    Here’s a study showing Tanners have 90% more Vitamin D than non-tanners.

    http://xr.com/TangVitD

  15. gee mumm on Sat, 15th May 2010 11:59 AM

    16. “Just look at us. Everything is backwards; everything is upside down. Doctors destroy health, lawyers destroy justice, universities destroy knowledge, governments destroy freedom, the major media destroy information and religions destroy spirituality” - Michael Ellner

  16. Cynthia Frederick on Mon, 17th May 2010 7:13 PM

    17. I appreciate the absolute logic behind the numbers. To give you perspective on how small a figure 0.1% => one-tenth of one percent is, think of comparing a dime to a $100 bill. You have 1 dime out of 1000 dimes as the difference between a non-tanner vs a tanner in developing melanoma. Thank you for your effort in presenting facts.

  17. Jessica on Fri, 21st May 2010 6:04 AM

    18. In a way, the recently approved health care bill on tanning beds are helpful especially that it brings awareness to the people on how to properly use it. Responsibility should always comes first. If you want to feel and look beautiful, make sure you do it the right way.

  18. Coverage of bacon, cell phones doesn’t add up : Covering Health on Mon, 24th May 2010 10:15 AM

    19. [...] In the story about bacon and heart disease – which runs with a headline that declares “A bacon sandwich a day raises risk of heart disease by half” – she notes the Daily Mail reports “the risk of heart disease goes up by 42% with every two-ounce (about 56g) serving of processed meat.” Williams calls the 42 percent increase as small in epidemiological terms. The Daily Mail also doesn’t tell readers if that is the absolute risk or the relative risk. [...]

  19. pale face on Fri, 28th May 2010 2:46 AM

    20. Pardon me, but 1dime out of 1000 is still one dime too many when it comes to melanoma. Thousands of people tan in these beds, so yes, what do the numbers REALLY mean?
    And speaking of coins, it only takes 50p per minute to tan in an unsupervised coin operated ’salon’ in the UK…. with tactics like this it’s no wonder the pale faces are fighting back.

    http://pediatrics.aappublications.org/cgi/content/full/121/5/1040

  20. Bruce W on Fri, 28th May 2010 7:20 AM

    21. Is it possible that sunbeds in a tanning salon are just much cheaper than an insurance co-pay on a monthly basis, and do the same thing for many patients?

    Interesting also that they use the word “safe” for their equipment.

    Phototherapy utilization for psoriasis is declining in the United States☆

    http://xr.com/UVPTdecline

    Tamara Salam Housman, MD, Janelle M. Rohrback, MD, Alan B. Fleischer Jr., MD, Steven R. Feldman, MD, PhD

    Abstract

    Phototherapy is an established treatment modality for psoriasis.

    The use of phototherapy for psoriasis appears to be in decline in nonfederal and non-university-based settings.

    We used data from the National Ambulatory Medical Care Survey to estimate the number of visits for phototherapy and psoralen ultraviolet A-range (PUVA) light therapy from 1993 to 1998.

    There were 873,000 visits for UV light therapy in 1993-1994, 189,000 in 1995-1996, and 53,000 in 1997-1998 (P < .0001).

    There were 175,000 psoralen visits in 1993-1994, 61,000 in 1995-1996, and 25,000 in 1997-1998 (P = .0053).

    Similar decreases in phototherapy visits occurred in our university-based practice.

    The decline in phototherapy represents decreased utilization of a safe and effective treatment for psoriasis. (J Am Acad Dermatol 2002;46:557-9.)

  21. Lou on Mon, 31st May 2010 10:22 PM

    22. I sure wish these doctors would leave the CMM and the minor skin cancers to the pros.

    Copious cutting edge research is showing unambiguously that sun exposure is PROTECTIVE against CMM.

    Is the sun an associative FACTOR in minor skin cancers? Absolutely.

    Is medical school an associative FACTOR in the malprescription of drugs? Absolutely.

    When will these doctors learn the difference between ASSOCIATION and CAUSE?

    Here is how much of the minor skin cancer is caused IMO.

    The at risk person consumes cheap processed polyunsaturated vegetable oils in excess amounts. Almost ANY is excess IMO. This puts the easily oxidized polyunsaturated oils in his skin. The sun oxidizes this easily oxidized oil beginning the skin cancer cascade.

    The person who will not get skin cancer does not ingest this cheap processed oil which is contained in junk food, fast food, processed food and all the garbage we will not eat if we wish to avoid ALL cancer, including skin cancer. The person who will not get skin cancer builds his skin oils from saturated fat, cholesterol and other oils that will not easily oxidize.

    Incidentally the sun is protective against ALL cancers and the cheap processed vegetable oils are a CAUSATIVE factor in most cancer IMO..

    http://healthyprotocols.com/2_cancer.htm

  22. So what does it take to get an embargo lifted early? « Embargo Watch on Tue, 1st Jun 2010 12:16 PM

    23. [...] of melanoma among those who used indoor tanning beds. (The press release, as it turned out, cited a guest blog post on relative and absolute risks I wrote earlier this month for the Association of Health Care Journalists’ Covering Health [...]

  23. July 1 marks a big day for health reform : Covering Health on Thu, 1st Jul 2010 9:55 AM

    24. [...] the chance of something happening – is far different. Reuters Health Editor Ivan Oransky, M.D., has written about the subject for Covering Health: “You can see how if someone is lobbying to ban something – or, in the case of a new drug, [...]

  24. Harmon Leon: Is Profit Behind Dermatology’s ‘Sun Scare’ Message? | Latest Global News on Tue, 13th Jul 2010 7:20 PM

    25. [...] past spring the Association of Health Care Journalists called into question dermatology’s math about melanoma. AHCJ reported a person’s risk [...]

  25. Dermotologist Undercover Sting!!! - tanTALK - Tanning Salon Business Owners Community on Wed, 14th Jul 2010 11:42 AM

    26. [...] of all cancer deaths–it isn’t even in the top 15 when it comes to cancer. This past spring the Association of Health Care Journalists called into question dermatology’s math about melanoma. AHCJ reported a person’s risk of melanoma is [...]

  26. HuffPo blogger claims skin cancer is conspiracy « White Coat Underground on Wed, 21st Jul 2010 1:20 PM

    27. [...] of the disease.  The problem of properly rendering statistics is a common one, and he links to an excellent piece by Ivan Oransky explaining the difference between relative risk and absolute risk.  Unfortunately, he [...]

  27. HuffPo blogger claims skin cancer is conspiracy « White Coat Underground on Tue, 27th Jul 2010 12:32 PM

    28. [...] of the disease.  The problem of properly rendering statistics is a common one, and he links to an excellent piece by Ivan Oransky explaining the difference between relative risk and absolute risk.  Unfortunately, he uses this to [...]

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