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What Risk Factors Can Lead to Alzheimer’s?

Ever since 1906 when Dr. Alois Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual “mental illness,” researchers have worked hard to learn all they can about what is called today, Alzheimer’s disease. Despite this extensive research, scientists still don’t fully understand what causes Alzheimer’s in most people. It’s likely that the disease develops as a result of multiple factors, which can include genetics, environment and lifestyle.

Researchers have been able to pinpoint factors that increase a person’s risk of developing Alzheimer’s. While some of these risk factors cannot be changed — age, family history and heredity — research indicates there may be factors over which a person does have some control. The importance of these risk factors in increasing or decreasing Alzheimer’s risk varies from person to person.

Causes of Alzheimer’s Disease

The exact cause of Alzheimer’s disease is not fully understood; however, at its core, Alzheimer’s occurs when brain proteins (beta-amyloid plaques and tau protein tangles) fail to function as they should. This causes a disruption in the way brain cells communicate with each other and unleashes a series of toxic events. Brain cells become damaged, lose connections with each other and eventually die.

The damage begins years before the first symptoms manifest and often starts in the hippocampus, the area of the brain that controls memory. As the damage increases, it often spreads in a fairly predictable pattern to other areas of the brain. By the time the disease reaches its late stage, the brain has been significantly reduced in size.

For a very small percentage of people who develop Alzheimer’s disease — less than 1% — researchers have been able to pinpoint that the disease is caused by specific genetic changes that essentially guarantee an individual will develop Alzheimer’s. Persons with this genetic component usually develop early-onset Alzheimer’s disease. It most often manifests in a person’s 40 and 50s; however, it’s not unheard of for people in their 30s to be diagnosed with early-onset Alzheimer’s.

Early-onset Alzheimer’s disease, also known as younger-onset Alzheimer’s, refers to cases where persons younger than 65 are diagnosed with the disease. Early-onset Alzheimer’s disease is more extreme than Alzheimer’s that is diagnosed after the age of 65 (late-onset Alzheimer’s). It’s much more aggressive and progresses a lot more quickly. People living with early-onset Alzheimer’s typically experience rapid deterioration. However, just as is the case with late-onset Alzheimer’s, the progression of the disease can be different for each individual, which means that some early-onset Alzheimer’s cases progress at a slower rate.

Although researchers are unsure what causes early-onset Alzheimer’s, their studies indicate that there’s a strong genetic component to the disease. It is believed that genetics play a much larger role in early-onset than it does in late-onset Alzheimer’s.

Risk Factors of Alzheimer’s Disease

Scientists believe a host of factors beyond genetics may be responsible for the development of Alzheimer’s. Many scientists are looking at the relationship between cognitive decline and metabolic conditions such as obesity and diabetes, as well as, vascular conditions such as high blood pressure, stroke and heart disease.

Researchers have found that the majority of Alzheimer’s are caused by a combination of genetic, environmental and lifestyle factors that affect the brain over time.


Although Alzheimer’s is not a normal part of the aging process, getting older does increase a person’s likelihood of developing Alzheimer’s disease. In fact, increasing age is the greatest known risk factor for Alzheimer’s disease. The risk of developing Alzheimer’s begins at the age of 65 and goes up from there. After the age of 65, the likelihood of developing Alzheimer’s doubles approximately every five years. By the time a person reaches the age of 85, their risk increases to nearly one-third.


There is very little difference in risk between the sexes. However, since women tend to live longer than men, more women are diagnosed with Alzheimer’s disease than men. According to Harvard Health, at the age of 65, for every 100 American women, there are only 77 men. By the time they reach the 100-year mark, there are four women for every one man. This disparity in numbers results in more women than men developing Alzheimer’s disease.

Family History and Genetics

We’ve already discussed the relationship between genetics and early-onset Alzheimer’s disease. Now, let’s look at how family history and genetics play into the likelihood of developing late-onset Alzheimer’s. A person with a first-degree relative who has developed the disease, such as a parent or sibling, are more likely to develop Alzheimer’s themselves. Researchers have identified mutations in three genes that essentially guarantee a person will develop Alzheimer’s if they inherit just one of them; however, these mutated genes account for less than one percent of all Alzheimer’s diagnoses. Additionally, if more than one family member develops Alzheimer’s, the risk increases.

When diseases run in families, it’s believed that genetics, environmental factors or a combination of the two may play a role in the development of the disease.

Down’s Syndrome

People with Down’s syndrome appear to have a higher risk of developing Alzheimer’s disease. Although researchers are unclear as to why, persons with Down’s syndrome often develop Alzheimer’s in their 30s and 40s. It’s likely to be related to having three copies of chromosome 21, the gene for the protein that leads to the creation of beta-amyloid.

Head Injury

Numerous studies over the last 30 years have linked moderate and severe traumatic brain injury (TBI) to a much greater risk of developing Alzheimer’s disease or some other form of dementia many years later. Even repeated minor brain traumas such as that experienced in a boxing match (even when not knocked out) and other sports can lead to dementia.

Mild Cognitive Impairment

Mild Cognitive Impairment (MCI) can be thought of as a stage between dementia and normal forgetfulness. MCI is characterized by a decline in memory or thinking skills that is greater than what is expected for a person’s age. As its name suggests, MCI is “mild” and does not prevent a person from functioning in work or social environments. An MCI diagnosis, however, does indicate a significant risk for the development of dementia. When MCI primarily affects memory, it’s more likely to progress into Alzheimer’s. Not everyone who develops MCI progresses to Alzheimer’s or dementia, however, most cases of Alzheimer’s begin with MCI.

Poor Sleep Habits

Studies suggest that impaired sleep can lead to the development of Alzheimer’s. Not getting enough sleep can elevate the brain beta-amyloid levels which can lead to the development of Alzheimer’s. Since sleep plays an important role in clearing away beta-amyloid from the brain, not getting enough sleep may also allow levels to increase high enough to cause Alzheimer’s. Consistently sleeping more than nine hours could be an early warning sign for Alzheimer’s. In fact, studies have shown that people who get more than nine hours of sleep each night generally develop Alzheimer’s within ten years.

Lifestyle and Heart Health

The same risk factors associated with heart disease may also increase a person’s risk of developing Alzheimer’s. These include:

  • High blood pressure
  • High cholesterol levels
  • Poorly controlled type-2 diabetes
  • Obesity
  • Lack of exercise
  • Smoking or exposure to secondhand smoke
  • Atherosclerosis

Since the brain requires adequate blood flow in order to receive the oxygen and nutrients it requires, it makes sense that anything a person can do to improve their cardiovascular health is important to brain health as well. Since these risk factors are often determined by a person’s lifestyle, these factors can be modified and improved to reduce a person’s risk of developing Alzheimer’s.


Latinos have a 1.5 times greater chance than their Caucasian counterparts of developing Alzheimer’s. African-Americans are approximately two times as likely to develop the disease when compared to their Caucasian counterparts. The reason for these racial differences is not well understood; however, researchers believe that Latino’s and African-American’s higher rates of vascular disease may put them at greater risk in the development of Alzheimer’s.

The Villages of Windcrest Can Help

Are you concerned that you or someone you care about may be developing Alzheimer’s and need help? We’re here for you. The Villages of Windcrest in Fredericksburg, Texas, offers specialized memory care programming, personalized to create lives filled with moment after moment of joy. Residents here are family and enjoy a special sense of community at The Villages of Windcrest. Contact us today to learn more.