The cause of Alzheimer's disease is unknown. Several investigators now believe that converging environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia.
The following risk factors for Alzheimer's-type dementia have been identified:
Advancing age
Family history
APOE4 genotype
Obesity
Insulin resistance
Vascular factors
Dyslipidemia
Hypertension
Inflammatory markers
Down syndrome
Traumatic brain injury
Although most cases of Alzheimer's disease are sporadic (ie, not inherited), familial forms do exist. Early autosomal dominant Alzheimer's disease is very rare, and accounts for less than 1% of cases; cases occur in at least three individuals in two or more generations, with two of the individuals being first-degree relatives. Typical Alzheimer's disease is sporadic, but there are gene variants (such as APOE4 genotype) that raise an individual's risk of developing sporadic Alzheimer's disease.
Epidemiologic studies have suggested some possible risk factors, such as previous depression. Other studies have suggested that factors such as education and long-term use of NSAIDs may have protective effects against developing Alzheimer's disease.
Midlife hypertension is an established risk factor for late-life dementia, of which Alzheimer's disease is the most common type. Among patients with hypertension, the use of any antihypertensive medication with the potential to lower blood pressure may reduce the risk for dementia. A brain autopsy study evaluating the link between hypertension and Alzheimer's disease found that patients using beta-blockers to control blood pressure had fewer Alzheimer's-type brain lesions on autopsy compared with patients taking no drug therapy.
Learn more about the etiology of Alzheimer's disease.
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Cite this: Fast Five Quiz: Test Your Knowledge on Key Aspects of Alzheimer's Disease - Medscape - Jan 19, 2021.
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