A study recently published in the journal Neurology studied over 1,000 people around the age of 79. At the start of the study none of them had dementia, though 109 of them had already developed skin cancer. During the course of the study, 32 more participants developed skin cancer, and 126 eventually developed dementia. Among those who developed dementia, 100 developed Alzheimer’s.
The researchers found that the participants who had skin cancer were about 80% less likely to have Alzheimer’s when compared to the people with no history of skin cancer. Among those with skin cancer, only two went on to have Alzheimer’s. The link was not seen with people who developed melanoma, and the correlation was not seen for other types of dementia, such as those related to circulatory issues. Study author Dr. Richard Lipton, a professor at Albert Einstein College of Medicine said, “the apparent protective effect is enormous, and we were surprised by the magnitude.” Lipton and his colleagues believe environmental factors could be contributing to this result. It’s theorized that people who are more active may be outside in the sun more. This in turn may put them at greater risk for skin cancer, but at a reduced risk of developing Alzheimer’s. It’s also possible that getting more exposure to the sun’s ultraviolet rays may also help to absorb more vitamin D.
Lipton points out however, that these results should not encourage people to stop using sunscreen or to protect their skin from ultraviolet rays. “Whatever we learn from this might lead to interventions. If it turns out the vitamin D hypothesis is correct, no doctor will say, ‘get skin cancer,’ but they might recommend taking vitamin D supplements.” Recently Lipton saw his dermatologist, and was diagnosed with squamous cell skin cancer. I said, ‘Oh good,’ because my mom died of Alzheimer’s disease and I live in fear of it. It’s not that having skin cancer makes it a guarantee, but you’re at a reduced risk and that provides a little upside to something that otherwise has only downsides,” he says. healthland.time.com 5/16/13