Dementia risk factors: what raises the risk and what may lower it

What dementia is

Dementia is not a specific disease. It is an overall term for a decline in mental ability that interferes with daily life, and it affects memory, thinking and behavior (CDC). MedlinePlus describes it as a loss of mental functions, such as memory, language, problem solving and the ability to focus, that is severe enough to affect your daily life (MedlinePlus).

Alzheimer's disease is the most common type and accounts for 60% to 80% of cases. Vascular dementia, caused by strokes or other problems with blood flow to the brain, is the second most common and accounts for about 5% to 10% (CDC). Other types include Lewy body dementia, frontotemporal dementia and mixed dementia, where more than one type affects the brain at the same time (CDC).

An estimated 6.9 million Americans aged 65 and older are living with dementia, about 1 in 9 people (10.9%) (CDC). Many older adults live their entire lives without developing it (CDC).

Risk factors that raise the risk

• Age. Aging is the biggest risk factor for dementia (MedlinePlus). Even so, dementia is not a part of normal aging (CDC).
• Family history and genes. Having close family members who have dementia raises the risk (MedlinePlus). Having a close relative, like a parent or sibling, with Alzheimer's disease increases a person's chance of developing it. About one-third of frontotemporal dementia cases are inherited through genes (CDC).
• High blood pressure. It can damage blood vessels and limit blood flow to the brain, and it raises the risk of stroke, which can also damage the brain (CDC).
• Uncontrolled diabetes. When diabetes is not managed, too much sugar in the bloodstream can damage organs like the brain (CDC) (MedlinePlus).
• Hearing loss. The CDC calls it a very important risk factor for dementia. Researchers believe hearing loss may make the brain work harder at the expense of thinking and memory, and it can leave people less socially engaged (CDC).
• Lack of physical activity (CDC).
• Smoking. Current smoking increases the risk of dementia, including Alzheimer's disease (CDC).
• Drinking too much alcohol. Over time, excessive drinking can lead to high blood pressure or brain injuries, both of which raise the risk (CDC) (MedlinePlus).
• High cholesterol. Along with diabetes and high blood pressure, it is one of the conditions that damage blood vessels and raise the risk of vascular dementia (CDC).
• Repeated head injury. Chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury, is one of the conditions that can cause dementia or dementia-like symptoms (MedlinePlus).

A CDC-cited study found that African American, Hispanic, and American Indian and Alaska Native adults were more likely to have these risk factors. The same groups are also more likely to develop dementia than other groups (CDC).

Which ones you can change

The CDC says nearly 45% of all dementia cases may be prevented or delayed (CDC). MedlinePlus adds that researchers have not found a proven way to prevent dementia, and that a healthy lifestyle might influence some of your risk factors (MedlinePlus). Both can be true: the risk can be lowered, but nothing guarantees you will not get it.

The CDC's advice is from its page on reducing dementia risk (CDC). These changes can also help lower your risk of other chronic diseases (CDC).

For people aged 39 to 64, the CAIDE dementia risk score estimates 20-year risk from midlife factors such as blood pressure, weight and cholesterol. It is not a test for dementia now.

Normal aging or a sign to report?

Some memory changes are normal with age, such as sometimes forgetting where you put your car keys, struggling to find a word but remembering it later, or forgetting the name of an acquaintance. These should not affect your daily life (CDC).

The CDC lists these signs that may point to dementia (CDC):

• Getting lost in a familiar neighborhood
• Using unusual words to refer to familiar objects
• Forgetting the name of a close family member or friend
• Forgetting old memories
• Not being able to complete common tasks on your own

Some people with dementia also have changes in mood or personality, or problems with balance and movement (MedlinePlus). See your health care provider if you notice any of these signs (CDC). Some memory problems are caused by treatable conditions, such as medicine side effects, a vitamin deficiency or a thyroid hormone imbalance, and can be reversed when the cause is treated (CDC).

Is there a screening test?

The US Preventive Services Task Force found the evidence insufficient to weigh the benefits and harms of screening older adults without symptoms for cognitive impairment (I statement) (USPSTF 2020). That is not advice against seeing a provider when you or your family notice changes. The cognitive impairment screening check explains what it means.

Common questions

If a parent had dementia, will I get it?

Not necessarily. A close relative with Alzheimer's disease raises the chance, but the CDC lists many things you can do to reduce your risk, such as being physically active and controlling your blood pressure (CDC).

Is forgetfulness always dementia?

No. Normal aging can bring some memory changes that do not affect daily life (CDC), and some memory problems come from treatable conditions (CDC). Forgetfulness is often the first symptom of dementia, though, so changes that get in the way of daily life are worth checking (MedlinePlus).

Why does an early diagnosis help?

The sooner the cause is found, the sooner treatment can start. Early diagnosis also gives time to plan finances, write advance directives, look at clinical trials and plan for care needs (CDC) (CDC).