Vitamin D

I recently posted on the new law in California that bans indoor tanning for those under 14, and prohibits 14-18 year old minors from using tanning beds without their parent's permission.  A few additional thoughts.

First, the purpose of my post isn't to advocate the use of tanning beds.

Second, I'm not arguing that there aren't risks to certain types of UV over-exposure, whether in a tanning bed or in the sun.  There most certainly are.  These risks, particularly for fair-skinned people, seem to include non-melanoma skin cancer (more common forms of skin cancer, though less deadly), melanoma (less common, more deadly), wrinkles (deadly to some, apparently), and other types of skin damage. 

Third, the typical experience in a typical tanning bed does not replicate the experience of being in the sun.  Tanning beds tend to go heavy on UVA, which doesn't stimulate the production of Vitamin D, and with higher intensity levels than most people would typically experience (particularly away from the equator).  Plus, people in tanning salons are exposed to an extremely high intensity, but low quality auditory waves, also known as shitty pop music.

Fourth, the indoor tanning industry is a lot like their core clientele: pretty ditzy.  I've asked various salons for the UV spectrum and intensity emitted by their machines and bulbs, but none of them seem to know.  This is the most informed response I've heard: "These machines are more UVB, but you'll get redder in them, so use these more expensive ones that are UVA." 

Fifth, I accept that minors shouldn't be allowed to engage in certain types of dangerous activities that adults are allowed to engage in.  Smoking cigarettes is addictive, and so on.

So I accept all that.  Those aren't my issues.  My issue is the growing tendency to try to legislate healthy behavior.

I have both moral and pragmatic issues with this.  Morally, I'll concede that I have a higher threshold for when the government is justified in stepping in -- I think individuals should have enormous discretion over decisions in their own lives.  But I'll put that aside for the moment to speak to pragmatic-minded people who are in favor of technocratic legislation of health decisions.  How does this process actually work in practice?

I called up the office of State Senator Ted Lieu to ask for the scientific references they are basing their decision on, and the cost-benefit analysis.  I was directed to a press release for the legislation (plus prior press releases on the topic).  At least I wasn't put on hold, and the response was quick and courteous.

The press release includes three links to one website: indoortanningreportcard.com, a site which opposes indoor tanning and supports legislation to restrict it, as well as a link to this short overview on radiation as a carcinogen.  No link to a cost-benefit analysis.

On the Indoor Tanning Report Card site, there are a few links to various papers, but get this.  They ran their own study and this was their top finding:

"Tanning salons located in states with youth access laws were more likely to require the teen to obtain parental consent to tan. However, youth access law (presence vs. absence) did NOT relate to whether teens had actually used indoor tanning. This may be because many parents are providing their consent."

Their top finding was that parental consent laws don't actually work.  Apparently, California didn't get the memo.  I found this astounding -- the main conclusion of the advocacy group is that the very type of law passed by California doesn't work.  (They advocate a total ban for minors.)

What about a cost-benefit analysis?  Still nowhere to be found.  Would it be so hard to make a single spreadsheet that has the following, with citations?

• # of minors who visit tanning salons
• increased risk of cancer based on visits as a minor (low, medium, high estimates)
• prevalence of those types of cancer
• severity of those types of cancer
• medical benefits of tanning bed use (any vitamin D?, complexion)
• compare with likely alternative: minors giving themselves sunburns on beaches or staying out of the sun entirely
• consider the social cost of having to look at more people with spray tans
• cost to enforce the legislation
• see how this compares with other activities we would never consider banning, like swimming, bike riding, watching TV, getting a driver's license at 16, and trick-or-treating on Halloween

If I'm going to be governed by a technocracy, then I at least expect there should be a one-page cost-benefit analysis of every single law and regulation that comes out of our government.  This probably won't have a big impact on the big stuff, which people will just disagree on, but it will have an impact on all this little stuff that abounds.  If you can't even do a cost-benefit analysis, then perhaps technocracy only works in theory.

When it comes to the science, I don't have time or space to adjudicate the debate in this post.  But here are other potential risk factors that this legislation ignores or won't address:

• Does the use of traditional sunscreens increase the risk of skin cancer?  Traditional sunscreens only block a portion of the UV spectrum and disassociate the signal of damage (a burn) from actual damage that is still happening.
• A society that rarely gets sun anymore, and then when we do get sun, it's way more than our body is prepared to handle
• General indifference to the long-term consequences of sun burns
• Diets and medications that make our skin more sensitive to the sun
• A base level of skin cancer inherent to certain skin types, even if people were never actually exposed to the sun or tanning beds
• Why do many melanomas appear on parts of the body that are usually not exposed to the sun?
• Whether regular, moderate exposure to the sun reduces the incidence of skin cancer

If the scientific community is still in disagreement about some of these issues -- and what constitutes a healthy relationship with the sun -- why would we ever expect our political system to arrive at good outcomes?

In and of itself, a law that bans tanning for those under 14 and requires parental permission for minor 14-18 isn't the end of freedom in America.  But it represents an increasingly aggressive mindset that is eager to micro-manage people's behavior, including banning fatty foods and salt.

1. The Voluntary Human Extinction Movement (so much self-loathing, it's hard to read)

2. Skinning a deer with obsidian (not gross, but they are skinning a deer)

3. Vitamin D deficiency and the benefits of sun exposure (finally getting some mainstream recognition)

4. Devastatingly even-handed criticism of the China Study, the vegetarian/vegan holy book, courtesy of Dr. Michael Eades

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, Time, NPR, 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. 

Part of paleo is about experimentation and discovery.  This winter I started experimenting with going to the solarium....better known as the tanning salon.  That's right, I went to the tanning salon.  Really courting medical controversy here.  So here's why I went.

My initial reason was to get a base layer and avoid a sunburn in Mexico.  I had signed up for the MovNat course in Mexico in mid-January, and it seemed prudent to get a base layer to make it less likely I would burn in Mexico.  Sun burns are what cause the most damage to your skin and most increase your chances of skin cancer.  My sessions were purposefully short duration (<7 minutes) and low intensity, and so I needed to do a few of them before I got a noticeable tan.

Healthy Vitamin D levels decrease your overall chances of getting cancer.  My reading of the literature indicated that 1) it's extremely difficult to get sufficient Vitamin D from food and even supplements, 2) the deadly forms of skin cancer are more rare than generally thought, 3) they don't seem connected to sun exposure per se (sun burns are the more likely culprit), and 4) and your higher chances of getting skin cancer are far outweighed by the cancers you avoid by getting enough Vitamin D.  Use of a tanning bed -- with the right UV frequencies -- has also been shown to increase Vitamin D levels.  As for a few more wrinkles as I get older, that seems to be true, but I just don't care.  For an excellent overview of what we know about the sun, Vitamin D, and cancer, watch this video by Dr. Michael Holick at BU.  (He doesn't endorse tanning.)

My mood improved immediately.  I don't know what to say, it just did away with the winter doldrums.  The first time I went was in early January in New York City.

Now, would it better to get moderate sun exposure?  Yes.  Would it be better to have a UV solution in winter that mimicked natural sun light? Yes. Is it a good idea to go to the tanning salon to get burnt to a crisp in 10 minutes?  No, of course not. 

Who could benefit most from going to the solarium?  People with dark skin.  Dark-skinned people are adapted for an equatorial environment with enormously high sun exposure all year round.  It's as if they are wearing high SPF skin block all the time.  They need more sun to generate the same amount of Vitamin D as a fair-skinner person.  So black people who live in high latitudes or who live near the equator but are covered up all the time are particularly at risk.  Bad news for burqas -- blocking out the sun is causing rickets and osteoporosis in Middle Eastern women.  From the abstract: