1. Alzheimer’s disease was first identified more than 100 years ago.

But it wasn’t until 70 years later that it was recognized as the most common cause of dementia, according to the Alzheimer’s Association. 

2. It mostly affects older people, but we’re not sure why.

Why Alzheimer’s is largely associated with older adults is still a mystery. However, most research points to a series of age-related changes in the brain, like atrophy, inflammation, and the creation of unstable molecules. Nearly half of people over 85 get Alzheimer’s.

3. Early-onset Alzheimer’s is usually genetic.

People who develop Alzheimer’s before 60 usually do so because they’ve inherited one of three genetic mutations. This group accounts for about 5 percent of people with Alzheimer’s.

4. Not getting enough sleep could up your chances.

Amyloid, a memory-robbing protein, builds up in your brain when you get too little sleep, according to a recent study. And that type of protein is thought to attack the brain’s long-term memory and trigger Alzheimer’s. 

5. The less schooling you have, the more likely you are to get Alzheimer’s.

People who have spent fewer years in school are at higher risk for Alzheimer’s and other forms of dementia than those with more years of school. Researchers say that’s because schooling increases the number of connections between neurons in the brain.

6. Family history increases your chances.

You don’t need a family history of Alzheimer’s to contract the disease yourself. But people with a sister, brother, or parent who has Alzheimer’s are more likely to develop the condition. 

7. People with Down syndrome are likely to get Alzheimer’s.

Many people with Down syndrome get Alzheimer’s, says the Alzheimer’s Association. It may be because they have an extra chromosome 21, and that gene appears to be involved in the production of amyloid, the memory-robbing protein. 

8. Depression can be a sign of Alzheimer’s.

Early symptoms of Alzheimer’s include difficulty remembering names, events, or recent conversations. They might also include depression and apathy. Later symptoms can include disorientation, poor judgment, unusual behavior, and impaired communication.

9. Sometimes, symptoms are actually caused by something else.

Sometimes, unrelated conditions cause similar symptoms to dementia. These conditions are usually treatable, and include depression, thyroid problems, excessive alcohol use, medication side effects, and delirium. 

10. There are many ways to diagnose Alzheimer’s.

Your doctor might look at your medical, family, and psychiatric history, conduct cognitive tests and physical exams, or have you undergo a diagnostic workup including blood tests and head scans. 

11. Your friends can be involved in diagnosis.

Sometimes, doctors will ask relatives, friends, or other people close to you if they’ve noticed any changes in your behavior or in the way you think. 

12. Fifteen million Americans care for people with Alzheimer’s.

More than 15 million Americans are caregivers for people with Alzheimer’s disease and other dementias, says the Alzheimer’s Association. They are usually spouses, friends, or family members. 

13. They provide almost 18 billion hours of care every year.

Each year, caregivers for people with Alzheimer’s and dementia provide 17.9 billion hours of unpaid assistance. That’s valued at $217.7 billion, which is eight times the total 2013 revenue of McDonald’s. 

14. Playing music can reduce your risk of Alzheimer’s.

Want to reduce your risk of Alzheimer’s? Mayo Clinic says that socially and mentally stimulating leisure activities can help, like playing music, reading, or even playing challenging mind games.