Wealth and Skin Cancer

An interesting new study was just published revealing an increased incidence of melanoma among higher-income women in California.

The article: http://www.latimes.com/health/booste...0,865739.story

The study: http://archderm.ama-assn.org/cgi/con...rmatol.2011.44

Well, wealthy people have more time to tan, so it makes sense.

Originally Posted by Kajak

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Well, wealthy people have more time to tan, so it makes sense.

I just figured that the green dye in benjamins mutated more than one's ego...

blame Snooki

Originally Posted by Kajak

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Well, wealthy people have more time to tan, so it makes sense.

Actually, I may suspect it is also because the wealthy are probably more diligent users of chemical sunscreens, which may actually be accelerating the growth of malignant cells.

http://www.aolnews.com/2010/05/24/st...rating-cancer/

^^ Or people end up thinking they are immune to skin cancer when they put sunscreen on so end up staying under the sun for much too long.

Originally Posted by blahman

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^^ Or people end up thinking they are immune to skin cancer when they put sunscreen on so end up staying under the sun for much too long.
That certainly could be a part of it too. Although, I do think that limitations of daily sun exposure are largely inaccurate. Perhaps the combination of prolonged exposure and the chemical sunscreens is the problem.

Originally Posted by mm84321

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That certainly could be a part of it too. Although, I do think that limitations of daily sun exposure are largely inaccurate. Perhaps the combination of prolonged exposure and the chemical sunscreens is the problem.
Edit: have a link to the full study on melanoma and vitamin A?

Originally Posted by mm84321

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That certainly could be a part of it too. Although, I do think that limitations of daily sun exposure are largely inaccurate. Perhaps the combination of prolonged exposure and the chemical sunscreens is the problem.

Its like anything else. Build up a tolerance slowly. Slowly darken your tan, don't get burnt in order to minimize skin cancer risk. Also use non-PABA sunscreens, since cheap crap is carcinogenic.

Originally Posted by HgaleK

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Edit: have a link to the full study on melanoma and vitamin A?
The only link I have is to an analyses of the study by the Environmental Working Group. The study was once made publicly available by the FDA, but it seems that they have since taken it offline. "Recently available data from an FDA study indicate that a form of vitamin A, retinyl palmitate, when applied to the skin in the presence of sunlight, may speed the development of skin tumors and lesions (NTP 2009). This evidence is troubling because the sunscreen industry adds vitamin A to 41 percent of all sunscreens." http://www.ewg.org/2010sunscreen/ful...cancer-growth/

My big issue is that studies find a lot of things, and not all of them are reinforced by further studies.

The one-year study involved a hairless mouse strain (SKH-1), a well-recognized model for photocarcinogenicity research (Bucher 2002; FDA 2009; Halliday 2000; Yan 2007). Both male and female animals were used, with 34-36 animals per group. Testing included two concentrations of retinyl palmitate, 0.1% and 0.5%, administered topically in a cream vehicle.

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Good, but a slightly larger sample size might be nice for future studies.

Most were withdrawn and sacrificed when at least one skin tumor or lesion reached a significant, defined size. Though FDA did not publish the size at sacrifice for this study

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Most is unspecific and we have unpublished, though relevant data.

Some animals may have been withdrawn before tumors and lesions reached that size if skin lesions began to merge (which would make it difficult to assess skin effects), or if the animals were otherwise ill.

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Some and may are both unspecific. Also, we now have multiple reasons for removal from testing.

The reason for withdrawal is not available in the public data, so EWG was unable to distinguish between animals withdrawn because of large tumors, large lesions, or other reasons.

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No data presented on the reasons for removal from testing. We are now dealing with lesions, tumors, and anything else in unspecified amounts, and all recorded as being the same thing.

EWG analyzed differences in the number of days recorded for each animal’s survival, a proxy for rate of tumor or lesion development.

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We're mixing terms here and using data that doesn't necessarily mean anything at this point.

The data show that at least 89 percent of vitamin-A exposed animals developed one or more tumors during the study, and large tumors were likely a significant reason for withdrawals.

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They're exposing them to a lot of radiation, so of course they're going to develop tumors. In fact, these mice are used because they're likely to develop tumors: "The hairless mouse is highly susceptible to skin cancer, tumors and lesions under the conditions of this test." What percent of the non vitamin A coated animals developed tumors? We apparently don't even know whether or not the tumors were the cause for withdrawal (which we've somehow managed to redefine as survival in this article).

As a result, the speed at which these types of skin damage develop is an accepted indicator of harm

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Good bull! Show me a data set that includes time till first incidence of lesion or tumor and the growth rate and this study will shed some light on the issue at hand! But wait... we having nothing.

EWG analyzed differences in the number of days recorded for each animal’s survival, a proxy for rate of tumor or lesion development.

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Lets go back to this one again. We're using withdrawal under dubious circumstances as a proxy for survival, which we're using as a proxy for rate of tumor or lesion development.

Animals treated with retinyl palmitate were withdrawn from the study 11-to-21 percent sooner than animals whose skin was treated with a neutral cream and exposed to the same doses of UV.

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When did we get back to withdrawn? Also, how did we come to this 11-to-21 percent? The study took place over a year and is getting results that are a function of time. If Matthias mouse gets chlamydia and decides to bail on the study early (since we aren't controlling for non vitamin A related withdrawals) then all of our results get raped if we take an average.

Mice treated with only UV or only neutral cream combined with UV survived longer than animals exposed to vitamin A

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Glad to see that we're surviving again- it feels more heroic. What this should say is that the mice in this study exposed to vitamin A were, on average, removed for a variety of reasons sooner than mice treated with only UV or only neutral cream.


While caution is always advised, and being informed is important, this really is quite silly.

Originally Posted by HgaleK

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My big issue is that studies find a lot of things, and not all of them are reinforced by further studies.
Which is exactly why subsequent studies need to be conducted. I appreciate your interpretation of the findings; it is important to be an honest skeptic. But we cannot rule anything out until it has been proven beyond a reasonable doubt.

Originally Posted by mm84321

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Which is exactly why subsequent studies need to be conducted.

I appreciate your interpretation of the findings; it is important to be an honest skeptic. But we cannot rule anything out until it has been proven beyond a reasonable doubt.

I just hate alarmism created by manipulated data. I would love to future studies on this, but I can't take any of the results in this specific instance seriously. The analysis wouldn't have received a passing grade in a 100 level science course.