A new study found that people who get certain types of skin cancer are significantly less likely to develop Alzheimer’s disease (AD). U.S. scientists recently made this shocking discovery quite by accident. But as Louis Pasteur once said, “Chance favors the prepared mind.”
Actually, what he said was in French, but you get the picture.
Sometimes, chance observations may not make sense on the surface. But they lead to great insights and even greater understanding. So even in this era of multi-million dollar “planned” research studies, we should still pay attention to chance observations.
And thanks to this chance observation, we now know that getting certain forms of skin cancer reduces your Alzheimer’s disease risk. Now, we just need to figure out why it reduces your risk.
In a moment, I’ll tell you more about this fascinating new finding. And give some thoughts as to “why” and “how” it happened. But first, let’s go over some skin cancer basics.
There are three main types of skin cancer: melanoma, basal cell, and squamous.
When people think of skin cancer, they usually think of melanoma. This deadly form of cancer grows from the dark, pigment-producing cells in your skin. It often originates in, or around, moles and “beauty spots,” but not necessarily.
While sun exposure is a concern, some of the deadliest melanomas occur on the soles of the feet and palms of the hands–places not normally exposed to sun at all. It is a bizarre and terrifying cancer.
Fortunately, melanoma accounts for only a small percentage of skin cancer. And thanks to improved screening and treatment, 10-year survival rates for melanoma patients now reach 75 percent or more in western countries.
Basal cell cancer is the most common type of skin cancer. It originates from the bottom layer of your skin. This layer is more active, continually forming new skin cells. Squamous is the other common type of skin cancer. It originates from the middle layer of your skin.
Both basal cell and squamous cancers are easy to detect and treat, since they grow right on the surface of the skin.
They also have very moderate growth rates, compared to other cancers. Under the microscope, these cancers are so benign looking that we often assign them a “grade one-half.” Whereas, other cancers we grade in stages 1 through 4. The higher the grade, the more aggressive the cancer.
In addition, basal cell and squamous skin cancers do not metastasize to other parts of the body. If left completely untreated, the main worry is that they will grow down through the skin and ulcerate on the surface. We call this a “rodent” ulcer.
For example, Sen. John McCain–like many old sailors– had many basal cell skin cancers, but they never threatened his health.
Now, let’s get back to the skin cancer/Alzheimer’s disease connection. Researchers found that men and women who got basal cell and squamous skin cancer were 80 percent less likely to develop Alzheimer’s disease.
That is a truly astounding number. And it even has the study’s authors scratching their heads.
Which brings us back to the question–why?
Why does getting a non-aggressive skin cancer reduce Alzheimer’s risk? Remember, scientists want to know how and why something works…not just that it does work.
Other studies also found that having any type of cancer lowers your Alzheimer’s disease risk. This cannot be explained in terms of “competing risks.” In other words, that many patients would die from cancer before they live long enough to develop Alzheimer’s disease.
And the “competing risks” theory doesn’t explain these most recent findings because researchers adjusted for age to eliminate this kind of “competing risk.”
So what else is going on here?
One possibility is that getting more sun exposure–while it may cause more skin cancer–prevents Alzheimer’s disease. We already know that the vitamin D in healthy sun exposure protects against so many other diseases and medical conditions. It would not surprise me in the least if one day we find the same holds true for Alzheimer’s disease.
Further research should look at ecological correlations. For example, I’d like to see whether there is a geographic gradient for AD across sunny and not-sunny states in the U.S. We should also look at this among countries internationally.
Earlier studies have shown that there is a geographic gradient for non-skin cancers. In other words, people in climates with more sun have lower rates of many non-skin cancers.
Also, studies need to measure vitamin D levels in people with and without skin cancer. We should also begin to measure vitamin D in those who do and do not develop AD.
It’s also possible that people who are outside in the sun more often lead a healthier lifestyle overall. And this lowers their AD risk.
It’s even possible that people with AD simply don’t remember having had skin cancer, since it is much less serious than other types of cancer.
The study’s authors did not discover any specific “mechanism of action” that protects skin cancer victims from getting AD. So we don’t know if something biological happens in the body that protects them from AD.
As I said in my special report “The Insider’s Guide to Dodging Dementia,” it is surprising that so many questions remain unanswered by mainstream medicine when it comes to AD. Subscribers to my newsletter get this 7-page special report for free. If you have not yet become a subscriber, you can get started here.
1. “Nonmelanoma skin cancer is associated with reduced Alzheimer disease risk,” Neurology 2013; 80 (21): 1966