Scientists do not yet fully understand what causes Alzheimer’s disease, but it is clear that it develops because of a complex series of events that take place in the brain over a long period of time. It is likely that the causes include genetic, environmental, and lifestyle factors. Because people differ in their genetic make-up and lifestyle, the importance of these factors in preventing or delaying Alzheimer’s differs from person to person. In a very small number of families, people develop Alzheimer’s disease in their 30s, 40s, and 50s. Many of these people have a mutation, or permanent change, in one of three genes that they inherited from a parent. We know that these gene mutations cause Alzheimer’s in these “early-onset” familial cases. Not all early-onset cases are caused by such mutations. Most people with Alzheimer’s disease have “late-onset” Alzheimer’s, which usually develops after age 60. Many studies have linked a gene called APOE to late-onset Alzheimer’s. This gene has several forms. One of them, APOE ε4, increases a person’s risk of getting the disease. About 40 percent of all people who develop late-onset Alzheimer’s carry this gene. However, carrying the APOE ε4 form of the gene does not necessarily mean that a person will develop Alzheimer’s disease, and people carrying no APOE ε4 forms can also develop the disease. Most experts believe that additional genes may influence the development of late-onset Alzheimer’s in some way. Scientists around the world are searching for these genes. Researchers have identified variants of the SORL1, CLU, PICALM, and CR1 genes that may play a role in risk of late-onset Alzheimer’s.
A nutritious diet, physical activity, social engagement, and mentally stimulating pursuits can all help people stay healthy. New research suggests the possibility that these factors also might help to reduce the risk of cognitive decline and Alzheimer’s disease. Scientists are investigating associations between cognitive decline and vascular and metabolic conditions such as heart disease, stroke, high blood pressure, diabetes, and obesity. Understanding these relationships and testing them in clinical trials will help us understand whether reducing risk factors for these diseases may help with Alzheimer’s as well.
What causes Alzheimer's disease?
Scientists do not yet fully understand what causes Alzheimer’s disease, but it is clear that it develops because of a complex series of events that take place in the brain over a long period of time. It is likely that the causes include genetic, environmental, and lifestyle factors. Because people differ in their genetic make-up and lifestyle, the importance of these factors in preventing or delaying Alzheimer’s differs from person to person. In a very small number of families, people develop Alzheimer’s disease in their 30s, 40s, and 50s. Many of these people have a mutation, or permanent change, in one of three genes that they inherited from a parent. We know that these gene mutations cause Alzheimer’s in these “early-onset” familial cases. Not all early-onset cases are caused by such mutations. Most people with Alzheimer’s disease have “late-onset” Alzheimer’s, which usually develops after age 60. Many studies have linked a gene called {{ORGANIZATION}} to late-onset Alzheimer’s. This gene has several forms. One of them, {{ORGANIZATION}}, increases a person’s risk of getting the disease. About 40 percent of all people who develop late-onset Alzheimer’s carry this gene. However, carrying the {{ORGANIZATION}} ε4 form of the gene does not necessarily mean that a person will develop Alzheimer’s disease, and people carrying no APOE ε4 forms can also develop the disease. Most experts believe that additional genes may influence the development of late-onset Alzheimer’s in some way. Scientists around the world are searching for these genes. Researchers have identified variants of the {{ORGANIZATION}}, {{ORGANIZATION}}, {{ORGANIZATION}}, and {{NAME}} genes that may play a role in risk of late-onset Alzheimer’s.
A nutritious diet, physical activity, social engagement, and mentally stimulating pursuits can all help people stay healthy. New research suggests the possibility that these factors also might help to reduce the risk of cognitive decline and Alzheimer’s disease. Scientists are investigating associations between cognitive decline and vascular and metabolic conditions such as heart disease, stroke, high blood pressure, diabetes, and obesity. Understanding these relationships and testing them in clinical trials will help us understand whether reducing risk factors for these diseases may help with Alzheimer’s as well.