Alzheimer’s is the most common type of dementia and the sixth leading cause of death. The disease is characterized by mental deterioration that affects the memory, thinking, and behavior. It is estimated that 5.4 million Americans have Alzheimer’s. The number of individuals diagnosed with Alzheimer’s disease has shot up in the last years and is believed to continue to spike into the next few decades expecting the occurrence to triple. There is no cure for Alzheimer’s, but the treatment that slows the progression of the disease. This brings into question what risk factors are associated with Alzheimer’s disease? Some of the most talked about risk factors are age, obesity, diabetes, and genetics.
Age is the ultimate risk factor. According to Alzheimer’s Association, the majority of individuals with Alzheimer’s disease are above the age of 65. Only 5% of people diagnosed have early onset Alzheimer’s which occurs at a younger age within their 40s and 50s. It is thought that if an individual could live “forever” they would ultimately get Alzheimer’s because it is caused by the natural process of neurons not working correctly. Therefore, age is a major risk factor because of the natural process of the body and how the neurons get weaker as we grow older. However, it is still unknown as to why and what exactly happens that makes age the major risk factor.
Obesity has been shown to be a risk factor for Alzheimer’s as well. An obese individual is three times more likely to development Alzheimer’s. Eating healthy and exercise has been shown to decrease the effects and prevent neurodegenerative diseases, like Alzheimer’s. They prevent diseases through growth factors, such as BDNF and insulin growth factor (IGF1), which affect pathways, like ATK and GSK-3beta, that cause Alzheimer’s. Therefore, maintaining a healthy lifestyle decreases the risk of developing neurodegenerative diseases like Alzheimer’s.
Type III diabetes has recently become a nickname for Alzheimer’s disease. It is also referred to as a brain-specific form of diabetes. Insulin and insulin-like growth factors are essential for cell survival within the brain. The new name comes from the buildup of resistance to insulin or decreased the number of insulin receptors within the brain. If an individual has Type II diabetes that does not mean they will development Alzheimer’s because insulin resistance can vary between different organs. However, an individual with Type II diabetes is at a 50 to 65% higher risk of developing Alzheimer’s disease.
Genetics play a role as being a risk factor for two different types of genes; risk genes and deterministic genes, each can be heritable. Risk genes are genes linked to increasing the odds of developing the disease, but the presence of them do not cause the disease. An example would be if an individual inherits the gene APOE-e4, which is estimated to be present in 20-25% of cases. Deterministic genes cause the disease. If an individual inherits deterministic genes they will get Alzheimer’s, also called autosomal dominant Alzheimer’s disease (ADAD). An example would be the genes responsible for three proteins: amyloid precursor protein (APP), presenilin-1 (PS-1), and presenilin-2 (PS-2).
Risk Factors of Alzheimer’s Disease
