|What Causes Alzheimer's?
Scientists know that the symptoms of Alzheimer's are caused by dying brain cells and lower production of certain chemicals that send messages between nerve cells (neurotransmitters). The reasons why cells fail in this way is not clear. Similar to other chronic conditions (like diabetes or heart disease), Alzheimer's probably develops as a result of a mixture of complex factors rather than one overriding cause. We discuss those risk factors in this article.
Age and Alzheimer's
Although Alzheimer's is no longer considered a normal part of the aging process, the risk of the disease does increase with age. After the age of 65, the risk doubles every 5 years. By the age of 85, the risk is 50 percent.
Family History Of Alzheimer’s
Research shows 15 percent people with Alzheimer’s had a parent with the disease. The risk increases further if more than one family member (parent, brother or sister) develops it.
Genetics And Genes
There are 2 types of genes that influence whether you develop a disease or not. The first is a risk gene, these genes increase your risk of developing a disease but do not guarantee it will happen. The second is a deterministic gene, if you inherit this type of gene it guarantees you will inherit a disorder. Scientists have identified both risk and deterministic genes associated with Alzheimer’s. APOE is a risk gene that is implicated in about 20 to 25 percent all Alzheimer cases. Deterministic genes are rare and are limited to a couple of hundred extended families worldwide. They are thought to account for most cases of early onset Alzheimer’s which occur in people in their 40s and 50s (less than 5 percent of cases of Alzheimer's occur in people under 65).
Most experts believe that while genes play a role in Alzheimer's, they are not enough alone. A trigger is still needed to set the disease in motion. The following theories are being investigated:
Head injury: Studies show that people who suffer head injuries and concussion are more likely to develop Alzheimer's later in life. This is of particular concern for those in contact sports like boxing.
Strokes: Mini-strokes can result in the loss of brain cells and increase the risk of Alzheimer's.
Heart disease: The relationship between uncontrolled high blood pressure and Alzheimer’s is currently being investigated. One study shows a link between dementia and hypertension in midlife.
Gender: Women are twice as likely as men to develop Alzheimer's, but this may be because on average they live 6 to 8 years longer than men (see womens health statistics).
Education: Better educated people are less likely to be diagnosed with dementia. This may be because they are able to perform better on tests of intellectual ability and hide their symptoms. Or it may be that education somehow increases brain capacity, delaying the onset of Alzheimer’s for longer.
5 Myths About Alzheimer's
1. Aluminum can cause Alzheimer’s.
Not true. There was some concern in the 1970s that exposure to aluminum from everyday items like pots and pans and soda cans may cause Alzheimer’s. Studies since then have failed to find any link.
2. Artificial sweeteners cause memory loss
Insufficient evidence. For a while there were rumors that aspartame, an artificial sweetener used in many diet food and drink products may raise the risk of Alzheimer’s. The FDA stated in 2006, that it was satisfied there is not enough evidence to make this conclusion (based on more than 100 clinical studies).
3. Flu shots cause Alzheimer’s
Not true. An American doctor, who subsequently lost his license, issued a statement saying that the flu shot greatly increased the risk of Alzheimer’s. In fact many mainstream studies show the reverse. Older adults who receive flu shots are less likely to die sooner from all types of diseases, including Alzheimer’s.
4. Silver fillings increase the risk of Alzheimer’s
Not true. There was a scare for a while that mercury in silver dental fillings was toxic to the brain and could increase the risk of Alzheimer’s. A subsequent study by the National Institutes of Health (NIH) and article in the New England Journal of Medicine, concluded there was no such link.
5. Treatments exist that can halt the progression of the disease
Not true. At this point in time there is no treatment that can stop or halt the progression of the disease. Certain drugs may slow the progression of the disease temporarily in about 50 percent of patients, but the effects only last 6 to 12 months. Read more about the treatment for Alzheimer's.