What Causes Dementia?

What Is Dementia?

Before you learn about the causes of dementia, it may help to understand what dementia is. Dementia is an umbrella term that doctors use to describe several neurological conditions that affect how the brain functions over time. Though the symptoms of these neurological conditions vary, most interfere with individuals’ ability to remember, think and reason to the extent that they restrict daily life and activities. Many people with dementia experience personality changes and are unable to control their emotions and behaviours.

Until recently, it was a common belief that dementia — which was once commonly referred to as “senility” — was a common side effect of aging. This may be because as many as half of individuals 85 and older have dementia. However, more recent findings show that dementia is not a normal part of aging, that some people may be able to, if not prevent it, delay its onset, and that dementia can develop in midlife.

The Types of Dementia and Their Causes

Researchers categorize dementia into “types” to help providers ascertain their causes and level of permanency. The three types of dementia area as follows:

• Primary (neurological conditions and diseases in which dementia is the main and primary cause of the illness)
• Secondary (dementia that is due to an underlying condition or disease)
• Reversible, which occurs when dementia-like symptoms are the result of another illness or cause

Primary Dementia

There are five primary types of dementia. None of these are reversible and, to date, researchers are unclear as to what causes them:

• Alzheimer’s Disease: Alzheimer’s disease is the most common type of dementia and the term that many people wrongly use to describe all types of dementia. In a person with Alzheimer’s, two abnormal proteins build up in the brain: amyloid and tau. As these proteins build up, they disrupt the communication between nerve cells and the brain. Because of this disrupted communication, nerve cells die. As more nerve cells die, the proteins spread to further areas of the brain until the brain is unable to function normally.

The primary symptoms of Alzheimer’s include short-term memory loss, personality changes, behaviour changes and confusion. However, Alzheimer’s also causes long-term memory issues, speech difficulties and troubles walking.

Alzheimer’s typically affects older adults, with as many as 10% of individuals over the age of 65 and 50% of individuals over 85 afflicted by the disease. Family history plays a major role in a person’s predisposition for the disease, with between 60% to 80% of individuals who have Alzheimer’s having a strong family history.

• Vascular Dementia: Vascular dementia is the second most common type of dementia, affecting between 15% and 25% of all dementia patients. Vascular dementia is caused by damage the brain’s blood vessels, which typically occurs as a result of stroke or atherosclerosis. Symptoms of vascular dementia look similar to those of Alzheimer’s but are typically milder. Afflicted individuals may experience confusion, trouble concentrating, memory issues and difficulty completing tasks. However, the main difference between the two most common types of dementia is that vascular dementia tends to involve speed of thinking and problem solving rather than memory.

Cognitive decline in vascular dementia patients typically happens suddenly and after a triggering event, such as stroke or a series of mini strokes. Though not reversable, vascular dementia is typically preventable, such as by maintaining healthy blood pressure levels, preventing or managing diabetes, and/or maintaining healthy cholesterol levels.

• Frontotemporal Dementia (FTD): FTD is a common cause of early dementia, often affecting persons between the ages of 45 and 64. FTD occurs when abnormal proteins build up in the frontal and temporal lobes of the brain, as its name suggests. As these proteins accumulate, they cause damage to the brain, causing changes in personality, social behaviour and/or loss of language skills (understanding, speaking and forgetting the meaning of common words). FTD also causes loss of motor functioning. Approximately 5% to 6% of all dementia cases are FTD.
• Lewy Body Dementia: Lewy body dementia makes up between 5% to 10% of all dementia cases. In Lewy body dementia, clumps of protein, called Lewy bodies, build up in the brain’s nerve cells. These proteins damage the nerve cells and cause a myriad of symptoms, including but not limited to memory loss, changes in sleep patterns, planning and problem solving difficulties, balance issues, delusions and visual hallucinations.
• Mixed Dementia: In mixed dementia, which is most common in individuals over than 80 years old, two or more types of dementia combine to cause a host of issues. The most common combination is Alzheimer’s and vascular dementia, though other combinations can and do occur. Because the symptoms of the combined dementias often overlap, diagnosing mixed dementia can be tough and, therefore, difficult to manage. For this reason, individuals with mixed dementia often experience a swift decline in cognitive health.

Secondary Dementia

Secondary dementia refers to dementias that have secondary causes, such as other illnesses or disease. By identifying and treating the underlying cause of secondary dementia early on, healthcare teams may be able to prevent further cognitive decline in patients:

• Parkinson’s Disease: It is not uncommon for individuals in the later stages of Parkinson’s disease to develop symptoms of dementia. Common symptoms associated with Parkinson’s include memory loss, trouble with thinking, delusions, hallucinations and speech difficulties.
• Huntington’s Disease: Huntington’s disease is caused by a single defective gene. This gene triggers the breakdown of the brain’s nerve cells, which leads to the inability for one to control his or her body movements, thinking problems, memory issues, decision-making issues and personality changes.
• Wernicke-Korsakoff Syndrome: Wernicke-Korsakoff syndrome is a syndrome that stems from a severe thiamine, or vitamin B1, deficiency. Such a deficiency leads to bleeding in key areas of the brain that store and recall memory. The most common cause of this syndrome is alcohol use disorder, though chronic infection and malnutrition have been known to cause it as well. Symptoms of Wernicke-Korsakoff syndrome include loss of muscle coordination, double vision, and difficulties learning new skills, processing information, and remembering information or events.
• Creutzfeldt-Jakob Disease: This disease is a rare infective brain disease that afflicts just one in 1 million individuals. It is caused by an abnormal protein in the brain (prion) that clumps together to cause cell death. Symptoms of Creutzfeldt-Jakob disease include memory issues, communication problems, thinking difficulties, trouble planning or making rational decisions, behaviour changes, confusion, depression and agitation.
• Traumatic Brain Injury: Traumatic brain injury occurs after a severe blow to the head or repeated trauma to the head. People who typically develop TBIs include football players, war veterans, victims of car accidents and boxers. Symptoms of dementia may appear years to decades after the triggering event and may include slurred speech, memory loss, behaviour or mood changes, and headaches.

Reversible Dementia

There are some conditions that cause dementia-like symptoms that, with treatment, can be cured:

• Vitamin Deficiencies: Deficits of certain vitamins, such as vitamins E, B1, B6, B12 and cooper can cause dementia-like symptoms. Incorporating more of these vitamins into your diet can help reverse the symptoms.
• Normal Pressure Hydrocephalus: NPH is a condition in which cerebrospinal fluid (CSF) builds up in the spaces within the brain, or ventricles. This build-up can cause harm to the brain and trigger symptoms such as forgetfulness, poor balance, mood swings, difficulties paying attention, frequent falls and bladder control. It is typically caused by brain injury, brain infection, bleeding in the brain or prior brain surgery. Draining excess fluid through a surgically-placed stunt can relieve the brain of the pressure and return it to normal.
• Infections: Certain infections may cause dementia-like symptoms, three of the biggest culprits of which include Lyme disease, HIV infection and syphilis. Recent reports indicate that COVID-19 infection may cause acute delirium and “brain fog,” a hypothesis researchers attribute to the increased inflammation and stroke-risk associated with the disease. In elderly patients, it is not uncommon for urinary tract infections (UTIs) or lung infections to cause dementia-like symptoms. Other infections of the nervous system or brain, such as those caused by parasites, bacteria or fungi, may also cause cognitive dysfunction.
• Side Effects of Medication: Side effects of certain medications mimic the symptoms of dementia. Though side effects vary from person to person, types of medications that commonly cause dementia-like symptoms include anti-seizure drugs, anti-anxiety medication, sleeping pills, antidepressants, anti-Parkinson’s drugs, narcotic pain relivers and nonbenzodiazepine sedatives, to name a few.
• Metabolic and Endocrine Disorders: There are some conditions and diseases, such as liver disease, hypercalcemia, thyroid disorders, Addison’s disease, Cushing’s disease and hypoglycaemia, that cause symptoms that mimic those associated with dementia.
• Other Causes: Other conditions that may cause symptoms of dementia or similar to them include subdural hematomas (bleeding between the skull and the brain’s surface) and brain tumours.

If these conditions are caught and managed early on, you may be able to reverse the effects of dementia and restore normal or close to normal cognitive function.

Risk Factors for Dementia

Though researchers are unclear of what causes most causes of dementia, they have identified several risk factors. Some of those risk factors are uncontrollable, such as age and family history, while many you can control.

Risk Factors You Cannot Control

There are three main risk factors of dementia you cannot control. Those include age, family history and down syndrome:

• Age: The risk for dementia for any person, regardless of his or her family history or lifestyle, goes up with age. Though dementia is not a “normal part of aging,” as once thought, the risk does increase after the age of 65.
• Family History: Having a family history of dementia puts one at greater risk of developing it in older age. However, people with a strong family history never develop it, while those with no family history do. Though a risk factor, family history is not a strong indicator of future dementia.
• Down Syndrome: Many people with Down syndrome end up developing early-onset Alzheimer’s disease by middle age.

Risk Factors You Can Control

There are some steps you can take to, if not eliminate your risk of dementia altogether, at least reduce it. Some risk factors that are commonly associated with dementia are as follows:

• Cardiovascular Risk Factors: High blood pressure, build-up of fats in the walls of the arteries, high cholesterol and obesity are all factors that commonly cooccur with dementia.
• Diet and Exercise: Research shows that high risks of dementia are associated with lack of exercise. Moreover, while research has yet to identify one specific diet that can reduce the risk of dementia, it does indicate that dementia occurs more frequently in individuals who maintain unhealthy, fatty diets compared with those who eat wholesome diets rich in fruits, veggies, whole grains, nuts and seeds.
• Excessive Alcohol Use: Extensive bodies of research indicate that alcohol use disorder is linked to not just an increased risk of dementia but also, to an increased risk of early-onset dementia. These findings correlate with those that indicate that excessive alcohol use causes changes in the brain makeup and function.
• Diabetes: Diabetes, especially when poorly managed, is linked to high-risk rate of dementia.
• Depression: Though not well-understood, researchers are finding links between late-life depression and dementia.
• Smoking: Smoking can increase your risk of blood vessel diseases, which is thought to increase your risk of dementia.
• Head Trauma: Head trauma, especially repeated trauma, puts individuals at greater risk of Alzheimer’s disease. Several comprehensive studies found that in individuals over the age of 50, the risk of dementia and Alzheimer’s disease was significantly higher in those who had sustained a traumatic brain injury at some point in their lives. The risk increased for individuals who sustained more severe TBIs and/or who sustained multiple head injuries throughout their lives. Some studies suggest that the risk is greatest between six months and two years post-injury.
• Air Pollution: Animal studies indicate that air pollution can speed up the degeneration of the nervous system. Findings from human studies corroborate this, suggesting that air pollution exposure is associated with a greater risk for dementia.
• Vitamin and Nutritional Deficiencies: Low levels of certain vitamins and minerals, such as vitamin B-6 or vitamin D, can increase your risk of dementia.
• Sleep Issues: Individuals with sleep disturbances, such as sleep apnoea, may be at a greater risk of developing dementia than those who enjoy peaceful slumber each night.
• Medications: Most medications come with several adverse side effects, many of which include dementia-like symptoms. If you begin to develop memory issues, thinking difficulties, confusion, behavioural changes, loss of coordination, etc. — and if you are on one or several medications — talk to your doctor about drug alternatives.

Preventing Dementia

Just as there is no one “cause” of dementia, there are no guarantee for preventing it. However, by understanding the possible risk factors, you can take steps to boost brain health and lead a high quality of life. Some top, research-backed tips are as follows:

• Keep your mind sharp. Engage in mentally stimulating activities regularly, such as reading, playing word games, solving puzzles and memory training, to decrease the effects of dementia or delay its onset.
• Get active. At least 150 minutes of physical activity and regular social interaction may help to delay the onset of dementia and/or diminish its effects.
• Maintain a healthy diet. Though no one diet is proven to prevent dementia, a diet rich in fruits, vegetables, healthy fats and whole grains, such as the Mediterranean diet, can go a long way to reducing your risk. Because a healthy diet improves heart health as well, it may help to reduce cardiovascular-associated risk factors, too.
• Get plenty of vitamins. A healthy diet should supply you with the vitamins and nutrients you need to stay healthy. However, in case you do experience a deficiency, talk to your doctor about supplements or other things you can do to increase your vitamin intake, such as increasing your sun exposure.
• Quit smoking. Studies indicate that smoking increases individuals’ risks of dementia, as it causes blood vessel conditions. If you smoke, quit now for better health in the future.
• Take care of your heart health. Cardiovascular conditions such as high cholesterol, high blood pressure and diabetes, all contribute to an increased risk of dementia.
• Prioritize sleep. Get on and maintain a healthy sleep schedule. If you still feel unrested after a full eight hours of sleep, or if you experience bouts of insomnia, talk to your doctor about possible sleep disorders.
• Treat mental health conditions. If you live with mood or mental health disorders, seek the help you need to manage them in healthy and effective ways.
• Do not ignore hearing loss. Hearing loss is closely linked to cognitive decline. If you start to develop hearing loss, talk to your doctor about early treatment for it and ways to prevent future cognitive decline.