There are multiple causes for Alzheimer’s Disease (AD) and some causes may not have been discovered yet. In fact, the causes for any given person developing Alzheimer’s varies greatly and are difficult to determine. However, researchers have come up with a list of risk factors that may make a person more likely to develop Alzheimer’s disease. Similarly, researchers have identified factors that decrease the risk of developing Alzheimer’s disease. And finally, researchers have ruled out certain popular myths about what causes the disease.
In recent years there have been several myths about things that cause AD, including the following:
The things above are among the many myths about how one acquires Alzheimer’s, yet the truth is that none of these things cause the disease. Although researchers are not exactly sure what causes Alzheimer’s disease, they have ruled out the items on the list above.
While, as mentioned above, there is no exact known cause(s) of Alzheimer’s disease, it is believed that multiple factors are involved. The following are risk factors for developing AD, which means there is a greater risk of the disease if any of these factors are present.
Aging alone does not result in Alzheimer’s disease. However, as one gets older the chances of developing the disease increases. After age 65, a person’s risk for developing AD doubles every 5 years, and after the age of 85, approximately one in three people are inflicted with the disease (Alzheimer’s Association, 2018). That said, this isn’t to say that every senior will develop Alzheimer’s disease; it is not a normal part of aging.
An individual with an immediate family member (mom, dad, brother, or sister) with AD means the chance of developing the disease oneself is more likely. The more people in the family that has the disease, the greater the likelihood that other members will develop it. In particular, it is suspected that early-onset familial Alzheimer’s Disease (eFAD), which develops between ages 30-60, is caused by genetic mutations. According to the Mayo Clinic, approximately 5% of all people with AD have the early-onset type. Late-onset AD, which develops after age 65, is the most common type.
Down Syndrome is a genetic disease that causes mental impairments and characteristic body and facial features. AD is far more common in this population than in the general population. According to the National Down Syndrome Society (2018), it is estimated that approximately 30% of individuals with Down Syndrome will be inflicted with Alzheimer’s in their 50’s, while approximately 50% will be affected by it in their 60’s. Studies suggest that individuals who have a family history of Down Syndrome have a higher risk of developing AD.
The Centers for Disease Control and Prevention estimates approximately 1.7 million Americans suffer from head injuries (traumatic brain injury) every year. Injury that results in the loss of consciousness or amnesia is considered a traumatic brain injury. Early adulthood head injury is strongly associated with development of Alzheimer’s disease later in life. Injuries resulting in skull fractures and long periods of amnesia put a person at greater risk. Researchers are still trying to determine why and how head injury contributes to the development of Alzheimer’s disease. Protective headgear and seat belts should be worn as often as possible to reduce head injury.
Additional factors, which are below, are suspected to contribute to the development of Alzheimer’s disease. However, scientists are not sure as to their direct link to the disease. More research will be needed to better understand the relationship between these factors and Alzheimer’s disease. In addition to the factors below, several others, such as smoking, stress, and depression, may put people at greater risk for developing Alzheimer’s disease.
Naturally occurring substances or chemicals that are found in our surroundings are considered to be environmental factors. Exposure to an abundant amount of these factors can cause many health problems, including AD. Exposure to natural minerals, such as lead, zinc, and iron, and chemicals, like benzene, toluene, fertilizers, and pesticides may increase one’s likelihood of developing Alzheimer’s.
Women are at considerably more risk for developing Alzheimer’s than men. This may be because women generally have a longer life expectancy than men, and the rate of AD increases with age. In addition, lower levels of estrogen after menopause increase women’s chances of developing AD.
Cardiovascular disease is a class of conditions that affect the blood vessels and the heart. Ailments that cause the blood flow to the brain to be altered are considered cerebrovascular disease. Suffering a stroke is a cerebrovascular disease, and according to the Centers for Disease Control and Prevention, each year more than 795,000 Americans have a stroke. Diabetes, high blood pressure, cigarette smoking, and heart disease are the primary cause of strokes. When a stroke deprives the brain of blood, which contains oxygen and food, brain cells can be damaged or die. This can lead to a form of dementia called Vascular Dementia (VD).
Parkinson’s disease (PD) is a progressive and irreversible neurological disease that produces tremors, impaired balance, rigid movements, and extremely slow movements to routine tasks, such as getting dressed. According to the Alzheimer’s Association, approximately 50-80% of individuals with Parkinson’s will develop Parkinson’s Disease Dementia. The symptoms associated with PD and AD often times are very similar and are difficult to distinguish from the other. AD generally develops in late stages of PD. Similarly, individuals in the late stages of AD often have symptoms of PD.
Diets high in cholesterol and fats can put people at greater risk of developing Alzheimer’s. Foods high in these products are risk factors for heart disease and strokes, and brain damage occurs when these diseases starve the brain of blood (Morris, 2004). An association has been found to exist between obesity and increased development of AD and other types of dementia (Beydoun et al, 2008).
Several factors that may reduce the risk or actually prevent Alzheimer’s disease and other forms of dementia are currently being explored. For example, exercise, a healthy diet, having an active social life, and limiting alcohol appear to be important.