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September: Alzheimer’s month |12 September 2022

What causes Alzheimer’s disease?


As we continue to celebrate Alzheimer’s month, let’s look at the causes of this disease.

Scientists are still a bit baffled by what causes Alzheimer’s in most people, but evidence so far shows that it is probably caused by a combination of age-related changes in the brain, along with genetic, environmental, and lifestyle factors. Of course, the importance of any one of these factors may differ from person to person.

As we saw in our article last week, Alzheimer's disease is a progressive brain disease, characterised by changes in the brain that result in loss of neurons and their connections. These and other changes affect a person’s ability to remember and think and, eventually, to live independently.


Ageing and Alzheimer's risk

Older age does not cause Alzheimer’s, but it is the most important known risk factor for the disease. Globally, the number of people with Alzheimer’s disease doubles about every five years beyond age 65. About one-third of all people aged 85 and older may have Alzheimer's disease.

Scientists are learning how age-related changes in the brain may harm neurons and affect other types of brain cells to contribute to Alzheimer’s damage. These age-related changes include atrophy (shrinking) of certain parts of the brain, inflammation, vascular damage, production of unstable molecules called free radicals, and breakdown of energy production within cells.

However, age is only one risk factor for Alzheimer’s disease. Many people live into their 90s and beyond without ever developing dementia.


Genetics of Alzheimer's disease

Many people worry about developing Alzheimer’s disease, especially if a family member has had it. Just because you had a family member who had Alzheimer’s does not mean for sure that you’ll have it, too. However, it may mean you are more likely to develop it.

People’s genes, which are inherited from their biological parents, can affect how likely they are to develop Alzheimer’s disease. 

There are two types of Alzheimer's ‒ early-onset and late-onset. Both types have a genetic component.

Late-Onset Alzheimer's

Early-Onset Alzheimer's

Signs first appear in a person's mid-60s

Signs first appear between a person's 30s and mid-60s

Most common type

Very rare

May involve a gene called APOE ɛ4

Usually caused by gene changes passed down from parent to child



Health, environmental, and lifestyle factors that may contribute to Alzheimer's disease

Research suggests that quite a few factors beyond genetics may play a role in the development and course of Alzheimer's disease. There is a great deal of interest, for example, in the relationship between cognitive decline and vascular conditions such as heart disease, high blood pressure, stroke etc. as well as metabolic diseases, such as diabetes and obesity. In the Seychelles, quite a few cases of dementia are caused by over-consumption of alcohol.

Ongoing research will help us understand whether and how reducing risk factors for these conditions may also reduce the risk of Alzheimer's. A nutritious diet, physical activity, engaging in social activities, sleep, and mentally stimulating pursuits have all been associated with helping people stay healthy as they age. These factors might also help reduce the risk of cognitive decline and Alzheimer's disease. 

Early-life factors may also play a role. For example, studies have linked higher levels of education with a decreased risk of dementia. There are also differences in dementia risk among racial groups and sexes ‒ all of which are being studied to better understand the causes of Alzheimer’s disease and to develop effective treatments and preventions for all people.

If you want to talk to someone from the Seychelles Alzheimer’s Foundation, give us a call on 4324012 or 2817878. Our office at Espace (G04) is open on Wednesdays and Thursdays.




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