Alzheimer’s & Other Dementias

Alzheimer’s Disease

…and related dementias are degenerative brain diseases that damage neurons or nerve cells in the brain that are responsible for cognitive function. Although there are several types of dementia, Alzheimer’s disease is the most common type accounting for 60-80% of cases. All dementias are characterized as a decline in memory, language and problem solving skills, often profound enough to affect an individual’s ability to perform everyday tasks. Eventually, neuronal damage can affect the individual’s ability to carry out basic bodily functions such as walking and swallowing. Individuals in the final stage of the disease are often bed-bound and require 24-hour care.

There are several types of dementia. Of these, Alzheimer’s disease is the most common, the best known, and the most feared. It is considered a chronic disease, persisting for a long period with no known cure or effective treatment. A preclinical phase can begin 15-30 years before symptoms appear. During this time, nerve cell damage begins to take place. If symptoms are reported and evaluated early on, the individual may be diagnosed with mild cognitive impairment. At this stage, individuals may show some degree of memory loss, but are still able to complete such routine tasks as paying bills and managing medications, though these tasks may demand greater mental effort. Some individuals do not progress past the mild cognitive impairment stage. However, most individuals develop worsening symptoms, and they are ultimately diagnosed with Alzheimer’s or related dementia. Once diagnosed, three clinical phases are recognized: mild, moderate, and severe, with an average survival rate of 4 to 8 years after diagnosis. Nevertheless, some individuals can live as long as 20 years with Alzheimer’s. The stages of Alzheimer’s disease and related dementias are presented in Appendix D of Montana’s Alzheimer’s Disease and Dementias State Plan. While some medical professionals describe these stages a bit differently, the seven-stage approach is used here as it provides a more comprehensive description of symptoms and a clearer road map for what lies ahead. It is important to note that not all memory loss symptoms are dementia related. Anyone experiencing concerns regarding memory loss should have a thorough evaluation with their health care provider.

Although most people develop symptoms of dementia after the age of 65, some Individuals can experience signs of dementia beginning as early as their 30s. Individuals with young onset dementia experience a greater initial loss of cognitive abilities such as deficits in attention, visual information interpretation, and language. The trajectory of the disease shows a faster rate of decline compared to individuals with later onset Alzheimer’s. The diagnosis of young onset dementia is often delayed due to the insidiousness nature of the disease and because the first signs are often ignored or explained away, as stress or fatigue. The disease affects all aspects of their lives, their ability to be in the workforce, to maintain relationships and support, and to be independent. Therefore, there is economic disruption, intimacy, quality of life and well-being issues that may be more exaggerated in individuals with early onset dementia.2 These individuals may also have increased difficulty accessing mainstream dementia services often targeted for older adults, which may have age restrictions. CLICK HERE to read about Reducing the Risk of Cognitive Decline.

Alzheimer’s Disease and Related Dementias Risk Factors


Most people with Alzheimer’s disease and related dementias are diagnosed after 65 years of age. However, people can develop “early onset” dementia with noticeable symptoms in their 30s, 40s, and 50s.

APOE-e4 Gene

Individuals who have one copy of this gene (20-30% of the population) are three times more likely to develop Alzheimer’s dementia. Those with two copies (2% of the US population) are 8-12 times more likely.  Researchers estimate between 40-65% of individuals diagnosed with Alzheimer’s have one or two copies of this gene.

Family History

Individuals who have a first-degree relative such as a parent or sibling with Alzheimer’s disease are more likely to develop the disease than those who do not.

Mild Cognitive Impairment (MCI)

Individuals with MCI are more likely to progress to Alzheimer’s disease or related dementias than those without MCI.


Individuals with fewer years of education are at a higher risk of Alzheimer’s disease and related dementia. Some researchers believe that having more years of education builds a cognitive reserve that helps individuals better compensate for the changes in the brain that could result in dementia.

Social & Cognitive Engagement

Remaining socially and mentally active throughout life may support brain health and reduce the risk of dementia.

Traumatic Brain Injury

Brain injury increases the risk of developing Alzheimer’s disease and related dementias. Moderate injuries are associated with twice the risk of developing dementia, while severe brain injuries are associated with 4.5 times the risk.

Cardiovascular Disease

Evidence shows that the health of the brain is closely linked to the health of the heart and blood vessels. Many factors, such as those listed below, can increase the risk of cardiovascular disease and therefore increase the risk of Alzheimer’s disease and related dementias.  Important to note, however, is that these risk factors are modifiable, unlike other risk factors noted above.

  • Smoking
  • Obesity
  • Diabetes
  • High blood pressure (hypertension)
  • High cholesterol
  • Unhealthy diet and physical inactivity
Alzheimer’s Association. 2016 Alzheimer’s disease facts and figures. Chicago, IL: 2016 Contract No.: 4/26/16.