While the exact reason individuals develop the disease is unknown, it is thought to depend on a multitude of factors. Those factors are a combination of genetic, environmental, and lifestyle factors. Genetics play a very small percentage in a patient’s development of this disease; however, if the individual does fall into one of the few percent of the population in which there is a genetic history, then those individuals have a significantly higher risk of developing the disease in the future.

What are the Risk Factors associated with Alzheimer’s disease?

• Age
  Alzheimer’s disease is a disorder of the older population. Therefore, age is the greatest associated risk for patients developing Alzheimer’s disease. Patients greater than the age of 65 have an increased risk of developing Alzheimer’s disease; and with each decade above age 60, the risk increases two-fold.
• Genetics
  Genetics and family history also play key roles in determining which patient population is likely to develop this disease in the future. If there is a significant history of a parent or sibling having the disease, then the individual is at an increased risk of developing the disease. There are only a small percentage of patients who develop Alzheimer’s disease as a result of genetic mutations.One genetic mutation that researchers have identified as increasing the risk of individuals developing Alzheimer’s disease is the APoE4. These patients are at increased risk of developing this disease at some point in their lifetime.Patients with Down Syndrome are at an increased risk of developing Alzheimer’s disease. These patients will present with symptoms onset earlier in life. Women are at an increased risk as compared to men. Patients who already experience cognitive impairment or other memory issues may be at an increased risk of developing Alzheimer’s disease later in life. If a patient has a history of a traumatic head injury, then they may be at increased risk.
• Lifestyle and Co-morbidities
  While there is not any definitive/concrete information surrounding the cause and effect relationship between lifestyle and Alzheimer’s disease development, there are certain risk factors that have been thought to increase a patient’s risk of developing Alzheimer’s disease. These risk factors correlate with the risk factors of developing cardiovascular disease. Risk factors include sedentary lifestyle with lack of exercise, obesity, smoking, hypertension, hyperlipidemia, type II diabetes mellitus and lack of a balanced diet with fruits and vegetables.