Whats the cause of alzeimers in general?

Unknown: The best association is with aging, but a history of head injury, diabetes, high blood pressure, and elevated cholesterol can influence eventual dementia. Folks who do little exercise and/or intellectual tasks have increased risk also. Some dietary measures may be preventative, such as red wine, cold water fish, mediterranean diet, coffee.

Nobody knows: In most cases, it is not clear what are the causes of alzheimer's disease. In some cases, the cause is an abnormal gene but that is true in only about 5% of people with alzheimer's disease.