There have been various causes attributed to Alzheimer's disease. The most recent research shows that the presence of five genes related to inflammation and cholesterol metabolizing make the disease more likely in the elderly.
The gene APOE discovered in 1995 is considered the most important in predicting Alzheimer's. The likelihood of inheriting the disease is 400 times if 1 copy of APOE is received from a parent and 1000 times if received from both parents. APOE like the five new genes discovered, is involved in cholesterol metabolism in some way.
Amyloids (A-beta) are tiny particles that cause a build up of plaque on the brain seen in patients and are one of the first signs of Alzheimers. In later stages of the disease, tangled strands of protein called tau appear. Scientists are trying to find the reason for plaque build up in the brain and why the brain cannot get rid of it.
Cell proteins need to be correctly folded as otherwise they can crystallize and become insoluble. Cells are able to detect and refold misfolded proteins. However in diseased brains, cells are overloaded and unable to keep up with the number of misfolded A-beta proteins.
Research at the Scripps Research Institute has shown that when cholesterol reacts with ozone, a chemical is formed that increases the likelihood of misfolding protein. Inflammation is said to produce this ozone.
Further research at the University of California has shown that stress causes the release of cortisol - a hormone made from cholesterol. Cortisol also induces cellular proteins to misfold.
Read more on how to help slow or prevent Alzheimer's disease