Saturday, October 3, 2009

Age is the Largest Risk Factor for Alzheimer’s Disease

There are multiple known risk factors for the development of Alzheimer’s disease, including family history, genetics, diabetes, gender, and vascular health; however the largest risk factor is age. The inherited form of Alzheimer’s, early onset, is rare and effects people under the age of 65. Once a person reaches the age of 65, the likelihood of developing Alzheimer’s increases, as the person ages.

  • At 65 to 70 years your risk is about 1.5%
  • At 70 to 74 years your risk is about 3.5%
  • At 75 to 79 years your risk is about 6.8%
Experts estimate that the risk for Alzheimer’s disease doubles every five years after age 65 and by age 85, nearly half of all people have the disease.

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According to the Alzheimer’s Association report (pg 6)
“By age group, the proportion and number of the 4.9 million Americans age 65 and over with Alzheimer’s disease breaks down as follows:
* Age 65-74: 2 percent … 300,000 people
* Age 75-84: 19 percent … 2,400,000 people
* Age 85 +: 42 percent … 2,200,200 people”

And they estimate that “By 2050, the number of individuals age 65 and over with Alzheimer’s could range from 11 million to 16 million unless science finds a way to prevent or effectively treat the disease. By that date, more than 60 percent of people with Alzheimer’s disease will be age 85+.”

It is still a mystery, why age is the largest risk factor for the development of Alzheimer’s. Researchers at the University of Cambridge are seeking to find out why. By investigating the pathways (biochemical reactions) that regulate ageing and their interactions with the onset of Alzheimer’s disease they hope to find an answer.

Alzheimer’s disease is associated with the presence of amyloid protein plaques in the brain and the destruction of brain nerve cells. Researchers at the University of Cambridge are investigating what age related changes make the brain more susceptible to these plaques and consequent brain deterioration. Although the toxic proteins associated with Alzheimer’s are found in normal brains and develop throughout a regular human life cycle, they rarely cause disease in younger people.

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An important insight into the ageing process has come from the discovery that the insulin-signaling pathway has a role in determining lifespan. It has been shown that a reduction in activity of this pathway in organisms such as flies, worms and mice increases lifespan. The aim of this project is to investigate the interactions between pathways involved in the regulation of ageing and Alzheimer’s disease using fruit flies (Drosophila) as a model.

The fruit fly models replicate many of the features of the human disease. The researchers, led by Dr Maria Giannakou, will use the model to determine how ageing affects the sensitivity of the fly brain to the toxic protein and how other processes or proteins interact with the ageing process to increase or decrease toxicity. A better understanding of the interaction between the ageing process and the formation of brain plaques in Alzheimer’s disease could lead to potential new targets for drug design.

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