Alzheimer's Disease Causes, Stages, and Symptoms (cont.)
Howard Crystal, MD
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
What's the difference between Alzheimer's disease and dementia?
Dementia is a syndrome characterized by:
Although some kinds of memory loss are normal parts of aging, the changes due to aging are not severe enough to interfere with the level of function. Although many different diseases can cause dementia, Alzheimer's disease is the most common cause for dementia in the United States and in most countries in the world.
Who develops Alzheimer's disease?
The main risk factor for Alzheimer's disease is increased age. As a population ages, the frequency of Alzheimer's disease continues to increase. Ten percent of people over 65 years of age and 50% of those over 85 years of age have Alzheimer's disease. Unless new treatments are developed to decrease the likelihood of developing Alzheimer's disease, the number of individuals with Alzheimer's disease in the United States is expected to be 13.8 million by the year 2050.
There are also genetic risk factors for Alzheimer's disease. Most patients develop Alzheimer's disease after age 70. However, less than 5% of patients develop the disease in the fourth or fifth decade of life (40s or 50s). At least half of these early onset patients have inherited gene mutations associated with their Alzheimer's disease. Moreover, the children of a patient with early onset Alzheimer's disease who has one of these gene mutations has a 50% risk of developing Alzheimer's disease.
There is also a genetic risk for late onset cases. A relatively common form of a gene located on chromosome 19 is associated with late onset Alzheimer's disease. In the majority of Alzheimer's disease cases, however, no specific genetic risks have yet been identified.
Other risk factors for Alzheimer's disease include high blood pressure (hypertension), coronary artery disease, diabetes, and possibly elevated blood cholesterol. Individuals who have completed less than eight years of education also have an increased risk for Alzheimer's disease. These factors increase the risk of Alzheimer's disease, but by no means do they mean that Alzheimer's disease is inevitable in persons with these factors.
A majority of patients with Down syndrome will develop the brain changes of Alzheimer's disease by 40 years of age. This fact was also a clue to the "amyloid hypothesis of Alzheimer's disease" (see section in this article).
Medically Reviewed by a Doctor on 3/20/2015
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Alzheimer's Disease - Symptoms Question: Please describe the symptoms you or loved one experienced with Alzheimer's disease.
Alzheimer's Disease - Treatments Question: What stage of Alzheimer's disease are you or your loved one currently experiencing, and have any treatments been effective?
Alzheimer's Disease - Non-Drug Treatments Question: What non-drug treatments have been helpful with symptoms of Alzheimer's disease in a loved one or friend.
Alzheimer's Disease - Dementia Question: Has a friend or relative been diagnosed with dementia? What are her/his symptoms?
Alzheimer's Disease - Warning Signs Question: Do you have any of the warning signs of Alzheimer's? Please discuss your symptoms and concerns.
Alzheimer's Disease - Home Safety Question: In what ways have you made the home safer for a friend or relative with Alzheimer's disease?
Alzheimer's Disease - Medications Question: If your relative is on a medication for Alzheimer's, what changes have you noticed?
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