There are many risk factors for Alzheimer's disease. Some of these are modifiable while others are not. It is important to note that even if you have only a few or none of these risk factors, it does not guarantee than you will never develop Alzheimer's disease.

Age: Age is the strongest risk factor for determining your probability of developing Alzheimer's disease. The risk of developing the disease doubles every five years after the age of 65. Around 2% of people will develop Alzheimer's before the age of 65 however around 1 in 2 people over the age of 85 will have the disease.

Gender: Gender is a minor risk factor for Alzheimer's disease. Most scientific studies have found that women are at a slightly greater risk than men. One of the reasons for this is that women tend to live longer than men however even after adjusting for age, women are still at around 5-10% greater risk.

Education: Studies have found that those people who do not complete high school are almost 50% more likely to develop Alzheimer's disease than college graduates.

Head Trauma: Some studies have found that people who have suffered a head injury that resulted in the loss of consciousness are at a slightly greater risk of dementia.

Estrogen Levels: Women who have low estrogen levels are more likely to develop Alzheimer's disease. Women who receive estrogen supplements after menopause are less likely to develop Alzheimer's and other forms of dementia.

Heavy Metal Toxicity: Experiments in monkeys have suggested that exposure to lead, particularly in childhood, leads to the development of beta amyloid plaques in the brain that are a precursor of Alzheimer's disease.

Obesity: A recent study found that people with large waist sizes in middle age are more likely to develop Alzheimer's disease in later life. Waist sizes greater than 37 inches in women and 40 inches in men are considered dangerous.