Skepticism, Science & Pseudoscience

Beta-amyloid is a protein believed to be a cause of Alzheimer's. According to the study published in Biomolecules, a peer-reviewed biological journal, the brain may produce this protein as a defense mechanism when pathogens are introduced via the nasal cavity.

“There is even some evidence to suggest that [beta-amyloid] may have antibacterial properties as a defense mechanism against microbial infections in the brain,” the report said.

So yes, dirty fingers going up the nose may trigger the brain to produce these dementia-causing proteins.

https://eu.indystar.com/story/news/2024/02/07/alzheimers-disease-neuroinflammation-nose-picking-dementia-memory-loss-hand-washing/72505363007/

Nose picking is associated with health risks such as spreading bacteria and viruses. It can also trigger nosebleeds and may cause damage to the delicate tissues inside the nose.

https://www.medicalnewstoday.com/articles/nose-picking#summary