Alzheimer’s Disease

Alzheimer’s disease, the most common type of dementia, involves parts of the brain that control thought, memory, and language, identified by the German psychiatrist Alois Alzheimer in 1901. Now, it is one of the top 10 leading causes of death in the United States, especially among adults aged 65 years and older.

The causes of Alzheimer’s disease are not yet fully understood. There likely is not a single cause but rather several factors that can affect each person differently. Aging is the most well-known risk factor, while the strongest genetic risk factor is from an allele of the APOE gene. The disease progression is largely associated with amyloid plaques, neurofibrillary tangles, and loss of neuronal connections in the brain. However, there are other hypotheses suggesting other causes. Early diagnosis of Alzheimer’s disease is often mistaken for normal aging and the definitive diagnosis can only be made on brain tissue after death.

There is also currently no known cure for Alzheimer’s disease. Existing medical management can only improve the quality of life for the patient and their family.

As of 2020, there are an estimate of 5.8 million Americans aged 65 years or older who have had Alzheimer’s disease and it is projected to affect nearly triple to 14 million by 2060. In 2010 the costs of treating Alzheimer’s disease were projected to fall between $159 and $215 billion and projected to be more than doubled to between $379 and $500 billion annually by 2040. The death rates are also increasing, unlike other age-related diseases like heart disease and cancer.

Figure, Image of amyloid plaques from brain tissue.

Related Bibliography:
[1] CDC info page of Alzheimer’s disease
[2] Matthews, K.A., et al. Racial and ethnic estimates of Alzheimer’s disease and related dementias in the United States (2015-2060) in adults aged ≥ 65 years. Alzheimer’s & Dementia. (2018)
[3] Long J.M. et al. Alzheimer Disease: An Update on Pathobiology and Treatment Strategies. Cell. (2019)
[4] Picture: Walker LC. "Aβ plaques". Free Neuropathology. (2020)