This article explains risk factors associated with the development of Alzheimer's Disease (AD) and how people can minimize the chance of getting dementia.

A risk factor is anything that reduces or increases the person's chance of developing the condition. Some - but not all - risks can be controlled.

Researchers have discovered risk factors for Alzheimer’s disease (AD):

Age

This is the largest known risk factor for Alzheimer's disease.

The risk of developing Alzheimer's disease nearly doubles every 5 years in older age, so by the age of 95 nearly one half of that age population will have AD.

Gender

Women are slightly more likely to develop AD than men, even when the fact that women live longer than men has been taken into account.

Lack of the hormone estrogen, following the menopause is considered to be one factor in the development of AD. Studies have nevertheless suggested that hormone replacement therapy (HRT) has no beneficial effect in preventing the disease, and may even increase a woman's risk of developing the condition.

Men appear to develop vascular dementia more commonly than women. This may reflect the fact that the common risk factors for vascular dementia, such as high blood pressure and heart problems are more common in men.

Genetics

Having a parent, brother or sister with Alzheimer's disease increases one’s risk of developing the condition by two to three and a half times. The more people in a family with Alzheimer's disease, the greater the risk of developing the disease is.

There is a very rare condition that involves having a defective gene on chromosome 14 or 21. This appears to trigger Alzheimer's disease with early onset, often between the ages of 35 and 60 years.

A protein exists called Apolipoprotein E, of which each of us has a copy of one of three types. This affects the chances of getting Alzheimer's disease. If you have two copies of the E4 type, you have an increased risk of developing Alzheimer's disease. However, the E2 type appears to give protection against it.

Individuals with Down's syndrome (Trisomy 21) apparently develop the pathological changes but not always the clinical symptoms of Alzheimer's disease.

Medical conditions

Cardiovascular conditions such as high blood pressure, diabetes, hypertension, heart disease and stroke increases the risk factor of developing Alzheimer's disease. Cardiovascular problems can be avoided by giving up smoking, having a healthy diet, lowering cholesterol and taking regular exercise.

Diet

A balanced, healthy diet is linked to reduced vascular disease, preventing the Alzheimer's disease. Omega-3 fatty acids (found in oily fish, eggs and seaweed) are thought to prevent AD.

Lifestyle variables

• Smoking. Nicotine can protect against AD. However, researchers know that smoking causes cardiovascular and respiratory diseases that are themselves Alzheimer's disease risk factors.
• Insufficient exercise. Research results have shown that moderate regular exercise helps to prevent Alzheimer's disease.
• Alcohol consumption. Small amounts of alcohol taken regularly can be good for health. However, high alcohol intake has been found to increase the risk of dementia significantly.
• Head injury. Sometimes, amyloid is deposited in the brain soon after a head injury, and where this has happened, a positive link to the development of dementia has been found. Head trauma can follow vascular damage from strokes, high blood pressure, diabetes mellitus and atherosclerotic disease.
• Environmental toxins. High levels of aluminium (found in saucepans and other kitchen equipment) were once thought to correlate with a raised risk of developing Alzheimer's disease. This theory is now less popular as further research has not supported this theory.