Alzheimer’s disease (AD) is a terrible disease. Initial clinic signs and symptoms vary. Early symptoms are often chalked up to aging or stress. The most common early symptom is trouble remembering recent events. As AD advances, symptoms can include confusion, language problems, irritability, aggression, mood swings, and loss of memory for remote events. As the patient worsens they often withdraw from family and can’t recognize their own relatives. As the brain deteriorates, bodily functions are lost, leading to death.
In the year 2000 in the United States, AD prevalence was estimated to be almost 2% in the 65–74 age group, with the rate increasing to 19% in the 75–84 group and increasing up to 42% in the older than 84 group. It is often said that if you live long enough, you will get AD. To my knowledge, no studies have looked at latitude and AD, nor have any looked to see how common it is around the equator. It is more common among African Americans.
What about AD and sunshine? We all know by now that one bad thing sunshine does is increases our risk of skin cancer, in particular non melanoma skin cancer (NMSC). The more sunshine you get, the more squamous cells and basal cells skin cancers risk you have. Unlike melanoma, NMSC is more common on sun exposed areas of your body, such as the face and hands, and is more common among outdoor workers than indoor workers. While NMSC is common, it’s very almost always completely treatable.
Recently, Doctor Robert White, working with senior author Professor Joshua Steinerman, both of the Albert Einstein College of Medicine, discovered that NMSC is highly correlated with a reduction in risk of AD.
They studied 1,102 adults with a mean age of 79 years for an average of 3.7 years. A total of 141 subjects reported NMSC and 100 participants were diagnosed with Alzheimer’s dementia. NMSC was associated with reduced risk of AD (hazard ratio 0.21), which means that NMSC appears to be extremely effective in preventing AD. Patients with NMSC were about 5 times less likely to get AD than were patients without NMSC. So for now, skin cancer appears to protect you from developing AD.
The authors had no good explanation for their finding but as NMSC is associated with sunlight and sunlight is associated with vitamin D, this study supports the vitamin D hypothesis that vitamin D may help in preventing AD.
The results of this study were so stunning, the effect size was so great, that it may be that vitamin D alone does not explain it. It may be that sunshine has benefits other than vitamin D that helps prevent AD. So be sure and get your sunshine while it is warm.