The short answer is we don’t know. Here is what we do know. The most common type of dementia, Alzheimer’s, affects 5.8 million Americans over 65 and is expected to grow to 13.8 million by 2050.

Here are some identified risk factors:

• Almost two thirds of Americans with Alzheimer’s are women.
• Older African-Americans are about twice as likely to have Alzheimer’s or other dementias.
• Hispanics are about 1.5 times as likely to have Alzheimer’s or other dementias.
• There is a link between head injuries and dementia.
• The risk of developing Alzheimer’s or vascular dementia appears to be increased by conditions that damage the heart and blood vessels.

Source: Alzheimer’s Association

Microscopic changes in the brain begin long before the first signs of memory loss. As damage in the brain spreads, cells lose their ability to do their jobs and eventually die. Two abnormal structures damage and kill nerve cells. Plaques called beta-amyloid build up in the spaces between nerve cells. Tangles called tau create twisted fibers that build up inside cells. While most people develop these as they age, those with Alzheimer’s tend to develop far more plaques and tangles and they begin in the areas of the brain involved in learning and memory and thinking and planning.

While there is no one thing you can do to prevent dementia, there is strong evidence that leading a healthy lifestyle may reduce your risk of dementia. Here are some tips to promote good overall health according to the Mayo Clinic:

• Avoid smoking.
• Control vascular risk factors including high blood pressure, high cholesterol and diabetes.
• Eat a balanced diet that’s rich in vegetables, fruits and lean protein, particularly protein sources containing omega-3 fatty acids (fish, chia seeds, edamame).
• Be physically and socially active, including aerobic exercise.
• Take care of your mental health.
• Use thinking (cognitive) skills by doing puzzles or Sudoku.
• Get enough sleep.

Young-onset Alzheimer’s, which affects those between the ages of 30-60, can be caused by mutations in certain genes. This type of dementia is rare.

Jan Petersen, a former foreign correspondent for CBS television and wife of CBS News correspondent Barry Petersen, was diagnosed with young-onset Alzheimer’s at the age of 55. The story of Jan and Barry is documented in the book Jan’s Story: Love Lost to the Long Goodbye of Alzheimer’s. See video clips and read more of their story here: https://www.cbsnews.com/news/former-cbs-news-correspondent-jan-petersen-dies-at-63/.

For more resources on dementia, visit The Alzheimer’s Association or call their 24/7 helpline at 800-272-3900.

Cat McGaffigan, Director of Independent Living & Supportive Services