Alzheimer’s causes and risk factors Scientists believe that a combination of genetic, lifestyle, and environmental factors influence when Alzheimer’s disease begins and how it progresses. Related topics: Alzheimer’s and dementia, Alzheimer’s symptoms and diagnosis, Alzheimer’s treatment, Alzheimer’s caregiving Thinking About Your Risk for Alzheimer’s Disease? Five Questions To Consider Learn what factors may contribute to your risk of developing Alzheimer's. Alzheimer's Disease in People With Down Syndrome Many, but not all, people with Down syndrome develop Alzheimer's disease when they get older. Learn about the connection between the two and how to participate in research studies exploring this relationship. Video: How Alzheimer's Changes the Brain This 4-minute video shows how Alzheimer’s affects the human brain and looks at promising ideas to treat and prevent the disease. What Causes Alzheimer's Disease? How does Alzheimer's disease affect the brain? Read how genetics, environment, and lifestyle play a role in developing early- or late-onset Alzheimer’s. What Happens to the Brain in Alzheimer's Disease? In Alzheimer's disease, damage to the brain likely starts a decade or more before memory and other cognitive problems appear. Learn about the toxic changes occurring in the Alzheimer's brain.