Non-melanoma skin cancer may protect against Alzheimer’s disease, according to new research published in Neurology.

The study included 1,102 people with an average age of 79 who did not have dementia at the start of the study. They were followed for about 3.7 years. At the start of the study, 109 people reported that they had skin cancer. During the study, 32 people developed skin cancer and 126 people developed dementia, including 100 with Alzheimer’s disease.

According to the findings, individuals who had skin cancer were nearly 80% less likely to develop Alzheimer’s disease than people who did not have skin cancer. Of the 141 people with skin cancer, two developed Alzheimer’s disease. The association was not found with other types of dementia.

Exactly how, or even if, skin cancer protects against Alzheimer’s is not known, but physical activity could be the mediating factor. Physical activity is known to protect against dementia, and outdoor activity could increase exposure to UV radiation, which increases the risk of skin cancer, the researchers suggest. The findings do not mean that people should stop taking measures to avoid skin cancer.