Neurodegenerative diseases affect millions of people worldwide. Alzheimer’s disease and Parkinson’s disease are the most common neurodegenerative diseases. In the United States, as many as 6.2 million people may have Alzheimer’s disease, according to a report from the Alzheimer's Disease Association in 2022.
Nearly a million Americans are living with Parkinson’s disease, according to the Parkinson’s Foundation. Neurodegenerative diseases occur when nerve cells in the brain or peripheral nervous system lose function over time and ultimately die. The likelihood of developing a neurodegenerative disease rises dramatically with age. In the coming decades, more Americans may be affected by neurodegenerative diseases, especially as life expectancy increases.
Scientists recognize that the combination of a person’s genes, and environment contributes to their risk of developing a neurodegenerative disease. For example, someone might have a gene that makes them more susceptible to Parkinson’s disease, but their environmental exposures can affect whether, when, and how severely they are affected.
We must improve our understanding of what causes neurodegenerative diseases and develop new approaches for treatment and prevention.