Through the ongoing research on dementia, we can now gradually understand the trajectory of brain decline, the stages of symptoms, and the multiple factors that raise the risks. There are still many things we don’t know.
Most studies today aim to uncover the cause of dementia as, until now, it remains unknown. What is recognized so far are the risk factors that older people use as a yardstick to gauge the possibility of developing dementia later on in their lives.
So what are these known risk factors for dementia? There are mainly five factors, and let's get to know each.
Age is a decisive factor for many diseases, including dementia. In an ongoing nationally representative study on the prevalence of dementia and mild cognitive impairment in people aged 65 and older, it was identified that 1 in 10 have dementia and 22% have mild cognitive impairment. The study was performed from 1992 to 2022 on 3496 older adults who have undergone thorough neuropsychological tests and interviews.
One key brain impairment symptom associated with age is forgetfulness. As we age, we occasionally forget things, but it isn’t always related to dementia. But the risk goes higher for people aged 65 and older who frequently experience memory loss.
Family History and Genes
Since there are different types of dementia, studies have conflicting points on family history and genes as risk factors, as it seems to vary based on the type of dementia the person has.
For instance, a rare subtype of Alzheimer’s known as Familial Alzheimer’s disease (FAD) is a form of dementia with a 50% high risk of the parents passing the disease to their children. This type of Alzheimer’s is caused by a mutation in three identified genes, potentially leading to children developing Alzheimer’s in their 40s or 50s. However, the number of cases of this type remains very few.
The majority of Alzheimer’s cases aren’t inherited. It’s the same with vascular dementia. Lewy body dementia1, another common type, is also rarely inherited. A gene variation causes it, but it doesn’t mean that if a person has this gene, they will develop dementia.
Experts strongly consider family history and genetics as critical risk elements for being diagnosed with certain types of brain impairment. Families with a history of dementia are assumed to have an elevated risk than those without a history.
Chronic Physical Conditions and Comorbidities
There are four major comorbidities in Alzheimer's disease, the most common form of dementia:
a) Hearing Loss
A 12-year study on 639 adults found that people with mild, moderate, and severe hearing loss are two, three, and five times more likely to have dementia, respectively.b) Vision Loss
Experts believe vision loss may be a risk for Alzheimer’s and other dementias. In a cohort study, older women with visual impairment were up to five times at increased risk for developing dementia.c) Cardiovascular Disease
Several studies established the link between cardiovascular diseases and dementia. One study determined that midlife hypertension could lead to the later development of vascular dementia and Alzheimer’s disease.d) Diabetes
White matter is a tissue in the brain made up of millions of nerve fibers (axons) that support the exchange of information and communication between other brain parts.
Diabetes is associated with larger white matter hyperintensities, and diabetes aggravates the risk of stroke by up to two times, which could lead to possible vascular dementia.
Lifestyle plays a huge role in keeping a healthy body and brain. It also affects the development of diseases in the same way. A positive lifestyle means a healthier quality of life, while a poor one equates to a higher vulnerability to illnesses.
There are four lifestyle components linked with a heightened risk of brain decline:
Alcohol has damaging effects on the brain. Abuse can lead to Korsakoff syndrome, a long-term memory disorder.b) Smoking
Analyses of various studies reported that smokers are 30% more likely to develop overall dementia and 40% more likely to develop Alzheimer’s.c) Inactivity
Older adults with a sedentary lifestyle who love to spend most of their time sitting and watching TV are at an increased risk of dementia, based on research.
The lack of exercise also impacts weight. Being overweight and obese contribute to an increased incidence of cardiovascular diseases.d) Poor Diet
Nutrition is as vital as sleep in brain health. A diet of saturated and trans fats, such as fried foods, dairy products, and other commercial goods, can trigger the possibility of cognitive decline.
There are some less-known factors that researchers consider to contribute to the damage to the brain.
- Mental Health (depression)
- Brain Injury
- Race and Ethnicity
- Environmental Factors
- Sleeping Position
Research on 1.7 million people aged 21 to 60 found that those diagnosed with a mental disorder are more than four times at risk of developing dementia than mentally healthy people. Depression is a common but preventable risk factor linked with dementia.
A traumatic brain injury (TBI) caused by an accident can impair many brain functions and cause depression, confusion, unconsciousness, difficulty learning and retaining new information, and more.
A late consequence of TBI, specifically years after the accident, is the escalated risk of having Alzheimer’s disease or other dementia.
Race and ethnicity contribute to cognitive impairment, too. A fact sheet published by the Alzheimer's Association shows that African Americans are about two times more likely to have Alzheimer’s and related dementias than Whites. Hispanics are about one and a half times at increased odds of developing Alzheimer’s disease and other dementias.
Black Americans’ higher likelihood for dementia is because of their greater risk for cardiovascular diseases attributed to their lifestyle and socioeconomic barriers, particularly in getting fair access to healthcare.
Everything from the environment that comes into contact with our body can affect our health, such as the water we drink, the air we breathe, and other types of pollution from our surroundings.
One review implied that the following environmental factors:: air pollution, aluminum, silicon, selenium, pesticides, vitamin D deficiency, and electric and magnetic fields provided moderate evidence in raising risks for brain deterioration.
Sleep is critical for brain health. When we sleep, the brain removes the toxins that have accumulated during wake times.
One surprising factor that can influence brain health is sleeping positions. Based on a study on 45 patients with neurodegenerative disease (NDD) and 120 cognitively healthy people, sleeping on the back for more than two hours each night occurs up to four times more frequently in participants with NDD. The study suggests that the supine sleep position may disrupt the brain’s ability to clear the neurotoxins during sleep, associating it with neurodegenerative disease.
Reducing the Risk of Dementia Starts With Learning the Triggering Factors
The advantage of knowing the precise cause of a disease is that physicians can recommend an appropriate treatment plan that guarantees to work. With dementia, the treatment method is likely all-inclusive, meaning it addresses all health domains, from physical, emotional, mental, and social.
Efforts to find a cure continue. For now, we can apply what we know about the risk factors and implement lifestyle changes to control our own health proactively.
Do you suspect some signs of cognitive decline in a loved one? Visit your doctor for a mental assessment.
Read our article What Are 10 Warning Signs Of Alzheimer’s? to learn how to spot warning signs for cognitive decline.
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