Defining Dementia and What It Does to the Brain

More than cancer, more than heart disease, dementia is on the minds of many Americans over 40. In fact, half of all adults aged 40 and older worry that they’re likely to develop dementia, even though heart disease and cancer are far more prevalent.
While worrisome, dementia isn’t a forgone conclusion. It’s not a natural part of aging, and many physicians and researcher feel that it’s largely preventable. 

But it helps to know more about dementia to begin with. 

Types of Dementia

The two most common types of dementia are Alzheimer’s Disease and Vascular dementia. Alzheimer’s accounts for 60 to 80 percent of dementia cases. Vascular dementia accounts for between 17 and 30 percent of the remainder. 

Other types of dementia are rarer but may include conditions you heard of: Lewy body dementia, frontotemporal dementia, Huntington’s disease and Creutzfeld-Jakob disease, among others. 

Here’s a quick rundown of the four most common types of dementia:

Alzheimer’s disease. The most common form of dementia in older adults, Alzheimer’s disease is a brain disorder that slowly, progressively destroys memory and thinking skills. Eventually, it prevents you from carrying out simple tasks.

Frontotemporal dementia. Caused by damage to the brain’s frontal and temporal lobes, frontotemporal dementia is also a progressive condition. Most cases (roughly 60%) occur in people ages 45 to 64.

Lewy body dementia. This disease is associated with deposits of a type of protein in the brain. The deposits, known as Lewy bodies, affect brain chemicals that play a role in thinking, movement, behavior and mood. There are two types of LBD: dementia with Lewy bodies and Parkinson’s disease dementia.

Vascular dementia. Vascular dementia results from injury to the vessels supplying blood to the brain. It can develop from the same risk factors associated with stroke, including atrial fibrillation, high blood pressure, diabetes, and high cholesterol.

Why do some get dementia with age and others don’t?

Most of us can expect some age-related memory loss, but it’s mostly a matter of brain health influenced by certain risk factors. Beyond age as the biggest risk factor, others include: 

• High cholesterol: linked to vascular dementia.
• Arteriosclerosis: the build-up of fatty plaque deposits in the arteries
• Depression: shown in multiple studies to double the risk of dementia.
• Diabetes: a high-risk factor for stroke and arteriosclerosis, both contributors to vascular dementia.
• Obesity: obesity is linked to dementia through other diseases it contributes to, namely heart disease and diabetes.
• Plasma homocysteine: high blood levels of amino acid homocysteine
• Instances of head injuries: head injuries can cause brain damage and lead to dementia.
• Certain medical conditions: including high blood pressure.
• Smoking and alcohol use: while research associates mild to moderate alcohol consumption with decreased dementia risk, heaier use is associated with dementia.
• Family history and genetics: family history can influence your risk, but just because an older relative suffered dementia doesn’t mean you will, too.
• Personality: Several studies, including by Stanford Medicine, also show a predictive link for increased risk between dementia and personality traits, specifically low conscientiousness, negative affect and neuroticism.
   

Preventing dementia

There’s no panacea for preventing dementia, and a cure remains elusive despite expanded research initiatives working towards that goal. And even if your risk factors are high – including genetics, prevalence of dementia among older relatives, heart conditions, depression and diabetes – you’re still not necessarily destined for dementia. 

There are proven defensive steps and everyday positive actions and health habits you can put into practice to help minimize dementia risk and lessen cognitive decline in your later years. 

Stay heart healthy and control high blood pressure: It’s the biggest risk factor for stroke, when a burst blood vessel or limitation of blood supply and oxygen can cause a brain bleed leading to vascular dementia.

Maintain a healthy weight and manage diabetes: Doing so helps regulate blood sugar levels and mitigates inflammation and damage to blood vessels in areas of the brain related to neurodegeneration and cognitive decline.

Eat a heart-healthy diet and exercise regularly: Our brain needs essential nutrients for optimum function and to help reduce inflammation. Physical activity increases blood flow and new brain cell growth.

Stimulate your intellect, keep learning and pursue hobbies: While it’s not yet clearly understood, there’s a positive correlation with continuing education and staying mentally active. Research suggests that education helps boost new synapse development in the brain and improve cognitive reserve.

Strive for quality sleep: Harvard Med School research found that people who sleep fewer than five hours a night or have fragmented sleep are twice as likely to develop dementia. Additional studies support that deep, quality sleep is necessary for the brain’s glymphatic system to flush out waste molecules, in particular the toxic protein amyloid, buildup of which can cause dementia. 

Protect your head: This goes without saying. Even slight head injuries can damage the brain resulting in cognitive decline over time.

Quit smoking: Multiple studies show that smoking reduces blood flow to the brain and increases risk of brain microbleeds, strokes and inflammation that can cause cell death and brain shrinkage.