What causes Alzheimer’s?

Why does Alzheimer's begin? What are its exact causes?

What causes Alzheimer’s?

Wondering why some people get Alzheimer’s?

Well, there is no definitive answer to this question, as experts have yet to determine the exact causes of this disease. What we do know is that there are a number of different factors associated with the onset and development of changes in the brain that lead to Alzheimer’s.

These risk factors include a combination of genetic, environmental and lifestyle factors. Their relevance, in terms of increasing one’s chance of developing Alzheimer’s, varies from person to person.

As each case is different, we cannot tell you the specific cause, so we have listed primary risk factors that increase your chances of developing the disease.

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Alzheimer’s is related to age

Over the age of 60, the chance of developing Alzheimer's doubles every 5 years
Over the age of 65, the chance of developing Alzheimer’s doubles every 5 years

Scientists are still researching how the changes in the brain that come with age affect nerve cells and contribute to the cellular damage identified as Alzheimer’s.

Over the age of 60, the chance of developing Alzheimer’s doubles every 5 years. Around a third of people over the age of 85 have Alzheimer’s.

However, elderly people are not the only ones who can suffer from Alzheimer’s. Approximately 1 in 20 cases of Alzheimer’s affect younger people aged between 30 and 50.

It can also be related to health, lifestyle and environmental factors

Obesity may increase the risk of Alzheimer's disease
Obesity may increase the risk of Alzheimer’s disease

A huge factor of healthy aging is lifestyle.

A healthy diet, physical activity, social commitments and mentally stimulating activities help people to stay healthy as they age.

These factors can help reduce a person’s risk of developing Alzheimer’s, along with other diseases such as heart disease, stroke, high blood pressure, diabetes and obesity (diseases that are often associated with Alzheimer’s).

There are some conditions that are not just associated with heart disease, but can also increase your chances of developing Alzheimer’s, including:

  • Smoking
  • Obesity
  • Diabetes
  • High blood pressure
  • High cholesterol

Alzheimer’s and Down’s syndrome

People with Down’s syndrome have a higher chance of developing Alzheimer’s. In fact, they usually start to show symptoms between 30 and 40 years old.

This is because the genetic fault that is responsible for Down’s syndrome also causes changes in the brain, which can lead to Alzheimer’s.

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Other risk factors associated with Alzheimer’s

Recent studies suggest that there are several other factors that can also play an important role in developing Alzheimer’s, although this is not to say they are directly responsible for causing this disease or other forms of dementia.

These factors include:

Recent studies have suggested a link between traumatic brain injury and developing Alzheimer’s, but research on this topic is still lacking.

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Alzheimer’s and genetics

Scientific research on this disease has revealed that genetics play a significant role in the development of Alzheimer’s. So bear with us while we get a little technical to help you understand the genetic factors that can contribute to Alzheimer’s.

Each human cell contains the instructions it needs to carry out its job. These instructions are made from DNA, which is found in each of the structures known as chromosomes. Each chromosome has thousands of segments called genes.

These genes are transferred from parent to child. They transport information that defines physical characteristics, such as eye color and height.

Genetics also play a fundamental role in the health of cells in the body. Genetic problems (including small changes to a single gene) can cause a number of different diseases, including Alzheimer’s.

The two types of Alzheimer’s

There are two different types of Alzheimer’s: early-onset Alzheimer’s and late-onset Alzheimer’s. Both types have a genetic component. Here are some differences between these two types of Alzheimer’s:

Late-onset Alzheimer’s

  • Signs start to appear after the age of 65
  • This is the most common type of Alzheimer’s
  • Can imply the presence of a gene called APOE ɛ4

Early-onset Alzheimer’s

  • Signs start to appear between the ages of 30 and 65
  • It is very rare
  • Usually caused by hereditary genetic changes

Late-onset Alzheimer’s

Most people with Alzheimer’s have late-onset Alzheimer’s, in which symptoms start to manifest after the age of 65.

Researchers have not found a specific gene that directly causes late-onset Alzheimer’s. However, there is a particular genetic factor that can increase your chances of developing the disease: having a form of a specific protein (apolipoprotein E – APOE) in chromosome 19.

So if one or both of your parents have this gene, you probably have it too. But remember that it is only a risk factor; having this gene does not necessarily mean that you are going to develop Alzheimer’s, but that you have a greater chance of developing the disease than other people.

Early-onset Alzheimer’s

Early Alzheimer's can occur from the age of 30
Early Alzheimer’s can occur from the age of 30

Early-onset Alzheimer’s (also known as younger-onset Alzheimer’s) can occur from the age of 30 and represents less than 10 percent of all cases of Alzheimer’s. These are caused by hereditary genetic changes that result in a type of Alzheimer’s known as early-onset familial Alzheimer’s disease (eFAD).

If one or both of your parents are carriers of the gene mutation that produces FAD, you have a 50/50 chance of inheriting that gene. If you have confirmed that you have definitely inherited this mutation, it is very likely that you will develop early-onset Alzheimer’s.

Have you been diagnosed with Alzheimer’s? do not panic. Information and support for this disease continues to grow every day and recent advances in technology have given us an unprecedented advantage in the discovery of new treatments for Alzheimer’s.

Why not share this article with your loved ones and help spread the word about Alzheimer’s?