<human>:  What are the causes of Alzheimer's disease?
<bot>: The exact cause of Alzheimer's disease is unknown, but it is believed to be a combination of genetic, environmental, and lifestyle factors. Genetics play a role as some people may have an increased risk due to certain gene variations. Environmental factors may include exposure to certain toxins or head trauma from falls or other injuries. Lifestyle factors such as lack of exercise, poor diet, and social isolation may also increase one’s risk for developing the disease.