What causes Alzheimer’s disease?
The causes of Alzheimer’s disease (AD) are unknown. Scientists believe that Alzheimer's disease may be caused by an abnormal buildup of proteins: beta-amyloid and tau. Beta-amyloid buildup forms plaques around brain cells. Tau deposits form twisted fibers called tangles within brain cells. As these proteins accumulate in and around the brain cells, the brain starts to lose its ability to function properly, this leads to loss of brain tissue, and eventually, the brain dies. The tissue damage also causes the affected parts of the brain to shrink (atrophy).
Initially plaques and tangles damage parts of the brain that control memory, thought, and language. Later they spread and damage other parts of the brain, leading to neuronal degeneration and progressive cognitive decline.
Risk factors for developing Alzheimer's disease:
The factors that increase the risk are:
- Age: Risk increases with age, affecting 15% of people older than 65 years and 50% of people older than 85 years.
- Family history: Family member with the disease increases the risk. Inherited gene mutations also increase the probability of developing the disease.
- Gender: Women have a higher risk than men.
- Down syndrome
- Traumatic head injuries earlier in life
- Other risk factors include:
- Cardiovascular disease
- History of depression
- Sedentary lifestyle