A recent study on tanning beds and melanoma has been making the rounds: "Indoor Tanning and Risk of Melanoma: A Case-Control Study in a Highly Exposed Population".  The WSJ, TimeNPR, and USA Today have all covered it.  The big statistic that everyone is throwing around is that "people who tanned indoors had a 74% higher chance of developing melanoma than those who hadn’t."  Note that the reason this paper is such a big deal is because there has never been strong evidence that using tanning beds caused melanoma.

Well, I had the great pleasure of meeting Dr. Michael Holick today, and we discussed this very paper.  You can view the full text here.  Let’s go the actual science and see what it says.

The 74% number comes from Table 3, second row, in the last column called multivariate adjusted OR (odds ratio).  You’ll see a 1.74 (hence, 74% more likely), plus a confidence interval.  (This interval, or error bounds, simply indicates that if you ran this experiment 100 times, 95% of the time you’d expect this value to fall between 1.42 and 2.14.)  The odds ratio for hours spent in a tanning bed increases to 3.18 (218% more likely) with duration of tanning bed use.

Well, from all the media hysteria, you’d expect that tanning beds would be the primary risk factor uncovered in the study.  And you’d be wrong.  Flip up to Table 2 and let’s take a look at the odds ratios of other factors.

Hair Color

What color is your hair?  Redheads have an OR of 3.53 — which means red heads are 253% more likely to get melanoma.  Compare that to the 74% number associated with ever having gone to the tanning salon.  And even blondes are 117% more likely (2.17 OR).  Having blonde hair or red hair has more to do with your risk of melanoma than whether you’ve ever gone to the tanning salon.  

Skin Color

Having very fair skin increases your chances of melanoma by a whopping 450% (5.50 OR).  Fair skin is 263% more likely, and even light olive skin is more important than having gone to the tanning salon.

Moles 

Moles!!!  If you have a bunch of moles you’re 1,281% more likely to get melanoma.  Having lots of moles is nearly 20X more important than whether you’ve gone to a tanning salon.

Lifetime Sun Exposure

Three measure of sun exposure show that high lifetime sun exposure decreases risk of melanoma (ORs of .85, .95, and .84).

Sun Burns

Sun burns, on the other hand, do increase your risk of melanoma, comparable to tanning salon usage.  

Mean Lifetime Sunscreen Use

Get this — THE SAME STUDY THAT CONNECTS TANNING BEDS WITH MELANOMA ALSO CONCLUDES THAT HIGHER SUNSCREEN USAGE INCREASES YOUR RISK OF MELANOMA.  Medium or High mean lifetime sunscreen usage increases your chances of getting melanoma by about 30%.  But somehow "Sunscreen usage causes melanoma" is a less catchy headline than "Tanning beds cause melanoma".

My point is not that there are no risks to tanning beds.  My point is that the biggest risk factors for melanoma are NOT tanning bed usage and are NOT sun exposure.  It’s having moles.  And red hair or blonde hair.  And fair skin.

So how about we do some science that actually tries to understand what’s going on, instead of attention-grabbing headlines that confuse and scare people. 


17 Responses to “Media hysteria on tanning beds and melanoma”

  1. Great post John!! 

     It just goes to show how easily the media can spin the results of a study in order to make it support their cause or create more buzz.  This same approach is done over and over with nutrition and it’s the reason why people are still terrified of fats and red meat.  I wish every study could be decompossed like this in order to expose the true learnings.

     

    • Anonymous says:

      Thanks for dissecting this study. Next I hope they can factor in distance from the equator and vitamin D status.

  2. Anonymous says:

    Are you suggesting that individuals with blonde/red hair or have relatively more moles on their body should avoid exposure to sun or tanning beds. Also, does this imply that there are benefits to using tanning beds, such as those associated with sun exposure?

    • John says:

      This is saying that if you wanted to reduce melanoma deaths, you would first talk to people with lots of moles and have them screened. Then you’d go find people with fair skin. Then red hair. Blonde hair. And then maybe you’d want to notify tanning salons.

      They don’t calculate any combinatorial odds in this paper, but it stands to reason that the more of those risk factors you combine, the more likely someone would develop melanoma. So a red-haired, fair-skinned, freckled, frequently burned, tanning salon customer with lots of moles would be particularly high risk.

      Also, it’s clear that sun burns also increase your chances of melanoma, and since fair-skinned people burn more easily, they would have a lower tolerance for being in the sun.

      This paper does not address benefits to sun exposure.

      • Ira says:

        John:

        Just a few points, from a middle-aged, freckly redhead who loves to run barefoot and barechested in the sun:

        1) Like you, I did experiment with tanning beds when I was your age. I’m not proud of it. I figured I could time my exposure more precisely and build up my tolerance more gradually than I could outdoors. I’m sorry I did; it’s really best to stick to natural  light. I have some non-cancerous acantholitic dermatitis called "Grover’s Disease," as well as more frequent non-threatening "basal cell" tumors as a result, I think. I also have had a few minor moles. Regarding moles, you mention moles as a risk factor, but I believe that some of my moles came about through tanning booth and sun exposure. Since my early experimentation, thank God, I stayed away from the booths. You fail to mention other research which I’ve seen elsewhere that there can be a kind of "high" from tanning, including tanning booth tanning, especially, which can be addictive, although I was never able to track down that research. I do think that it can feel addictive, and also because of that I urge caution. Of course, I do have some Seasonal Affective Disorder or S.A.D. in the winter, and that may put me a little more at risk for the "addiction" to tanning. But it’s better for me to get out to Brighton Beach or Coney Island, where the hardy Russian men go shirtless in the winter, than to use a tanning bed.

        2) I really think that a certain amount of imbibing of alcohol, to go along with our feasting on barbecued meat, is quite healthy for us men, and goes back to a very early time in our protoagruicultural hisory when special times would be reserved for drinking and sacrificing and feasting and beating our drums and performing our warrior dances.  I do, however, like to stick to basic, ancient, natural fermentation products like wine and beer, no more than twelve or thirteen percent alcohol. I don’t think our bodies were meant to take distilled alcohol products like vodka or Scotch or Cognac.  As long as I do that, I think I have fewer problems.

        -Ira

         

  3. Anonymous says:

    I feel like the reason that people who wear sunscreen more are more likeley to get melanoma comes simply from being in the sun more. If you wear a lot of sunscreen, chances are you are in the sun a lot, increasing your chances of getting melanoma.

    • John says:

      Yes, but note that the direct measures of lifetime sun exposure show a (slightly) negative relationship!

  4. Anonymous says:

    Good post, I know all too well about the dangers of the sun. I am a red head and I live at an elevation of 9,000 feat in northern New Mexico. I didn’t know that sun exposure decreases chances of melanoma; given that one avoids developing a sun burn.

  5. Anja says:

    Help! I’m red-haired, fair-skinned, I have lots of moles and I like to do my exercise outside also when the sun is shining. Should I stop the cavement diet because I will die soon on melanoma anyway? ;)

  6. marti783 says:

    Great post! I too am from the great state of Michigan and people really underestimate the potential benefits tanning can have on overall mood, especially in the winter.

  7. M@ says:

     The sunscreen issue is interesting from a chemistry standpoint. The compounds in the sunscreen will block UVB rays but will not block UVA rays. UVB rays cause burning whereas UVA rays are specifically implicated in the development of skin cancer. In addition, UVB rays stimulate the synthesis of vitamin D, which has potent anti-cancer properties. SO putting on sunscreen prevents the skin from burning but decreases vitamin D synthesis and does not block the carcinogenic UVA. This would explain why sunscreen is a risk factor for skin cancer.

    It looks like the best thing to do for fair skinned individuals is to gradually increase sun exposure in order to slowly build up a tan that will offer protection from both UVA and UVB.

    • John says:

      As I understand it, sunscreens used to only block UVB, but for the last few decades they block both.

      • M@ says:

         Companies have only recently begun dolling out products that block both UVA and UVB in an attempt to fix this "glitch".

        • Anonymous says:

           Also some SPF labels are false and don’t adequately reflect the protection within the bottle. And some people stay in the sun longer when they have sunscreen on than they would if they didn’t feel they had some sort of protection, which might explain why it’s higher risk.

        • Anonymous says:

           Oh, and in reply to your potential response about more exposure reducing the risk, if people are outside all the time and develop a darker skin pigmentation as a result, then that may be true, but if somebody exposes themselves more due to a false sense of protection from sunscreen on an irregular basis, they’re exposing virgin skin to the sun every time. Like me, I have blue skin (not as a disorder but I’m so fair I’m nearly transparent). If I go out into the sun with sunscreen on, I burn in four minutes. The burn, however, does not turn into a tan afterwards. I go back to blue, and my sensitivity of the sun just increases. Increased exposure can only logically reduce risk if more melanin is produced as protection. If exposure is intermittent enough that the melanin breaks down in between, then that type of expose would likely raise risk.

          There are too many factors involved. Even some forms of birth control and other medications increase sun intolerance. 

          But, imo, there really isn’t a need for tanning beds, especially not for prolonged periods. They’re not exactly natural, are they? Just because you simulate the components of sunlight, doesn’t mean you’re giving your body sunlight.

  8. Former tanner says:

    I wanted to share my story as I don’t want anyone to assume the sun is completely safe.  I decided to have my moles checked out after having my second child. I was an avid tanner.  I thoroughly enjoyed it, but I do believe that it played a part in my recent diagnosis.  I will admit that I did not wear sunscreen…until now, so I know that sunscreen did not cause my diagnosis. 

    I do not have red or blonde hair.   I have dark brown hair. 

    I went in to the dermatologist to have my moles checked out for the first time.  She took one look at a mole on my back – of which I didn’t know I even had – and said she didn’t like it.  It had a purple color in the middle and a blue halo around it.  The biopsy came back as severe atypia — actually, very severe (a step right below melanoma).  I had to go back to have more removed as the margins were not clear.  After the second round, they had caught it all. 

    I do attribute this to tanning.  My back was the closet to the bulbs.  Again, I had not worn sunscreen until recently.  Yes, the sun has many benefits and no one should run away from it.   There is a safe way to be in the sun.  Just remember, balance is key. 

    • Anonymous says:

      Three comments:

      1st of all I am glad that you were cautious about the mole, and had it removed whether it would progress into melanoma or not.  Now that you are limiting your sun exposure don’t forget about Vitamin D as there is very good evidence that it not only prevents the initiation of most forms of cancer, but also inhibits the progression of any that form.

      2   The evidence that sunscreen protects you from any type of skin cancer other than Squalmous Cell Cancer is not there, limit your time and cover up.

       

      3  Despite the hype about sunbeds, the risk of melanoma from using them is similar to having a higher level of education or using sunscreen, it is possible that your use of the tanning bed was helpful in your good prognosis and not the cause of the pre-cancerous condition.

      http://www.eblue.org/article/0190-9622%2892%2970007-3/abstract

       

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