brain health · Sep 04, 2025

What Are the Risk Factors for Dementia and Alzheimer’s Disease?

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Written by Liad Stearns, MS

Worldwide, more than 55 million people are living with dementia, with Alzheimer’s disease making up the majority of cases. In the United States alone, over 7 million people are affected [1]. Dementia not only impairs memory, but also removes one’s independence, puts strain on families, and is among the leading causes of death in older adults.

But while the numbers are striking, there are ways to age gracefully and keep your brain sharp. Research shows that changes in the brain can begin decades before symptoms appear, highlighting the importance of early awareness and detection. Advances in diagnostic tools, including highly accurate blood-based biomarker tests, are bringing us closer to detecting Alzheimer’s earlier and more efficiently [2, 3]. That’s why understanding your personal risk and focusing on early prevention can make a meaningful impact on your long-term cognitive health. At the same time, it’s never too late to adopt lifestyle strategies and interventions that support memory, cognition, and overall quality of life.

The Difference Between Dementia and Alzheimer’s Disease

Dementia is an umbrella term describing a set of symptoms that interfere with daily life, including memory loss, confusion, impaired judgment, and difficulty with communication or problem-solving. These changes occur when brain cells are damaged and can no longer communicate effectively. The effects depend on where the cell damage occurs, since different brain regions are responsible for different functions (e.g., memory, problem solving, balance).

Alzheimer’s disease is the leading cause of dementia, responsible for 60% to 80% of cases [1]. In Alzheimer’s, abnormal protein buildup disrupts brain cell health and communication, often beginning in the hippocampus (the brain’s memory center), which is why memory loss is a common early sign. Other forms include vascular dementia (linked to reduced blood flow), frontotemporal degeneration (damage to the frontal and temporal lobes), and dementia with Lewy bodies (caused by protein clumps). Mixed dementia, where more than one process occurs at the same time, is also common in older adults [4].

It’s also important to note that not all memory problems indicate dementia. Depression, thyroid disorders, vitamin deficiencies, alcohol overuse, or certain medications can cause similar symptoms and may improve with treatment [5].

Because many forms of dementia share overlapping risk factors, understanding both the differences and the similarities can empower individuals and families to take proactive steps for prevention and care.

Non-Modifiable Risk Factors for Dementia

Not all dementia risk factors are within your control, but awareness is still key.

Age: The greatest known risk factor for Alzheimer’s and other dementias. About 5% of adults ages 65–74 have Alzheimer’s, and this figure rises to over 33% by age 85 [6].
Genetics and family history: Having a parent or sibling with the disease increases an individual’s risk. Carrying the APOE-ε4 gene, particularly two copies, further increases the risk, though it does not ensure disease development [6].
Sex: Nearly two-thirds of Americans with Alzheimer’s are women. Researchers believe longer lifespan, hormonal changes at menopause, and possible genetic differences all contribute [6].
Ethnicity: Black and Hispanic Americans face a higher risk compared to white Americans. This disparity is linked to a combination of genetics, higher rates of cardiovascular disease, and social determinants of health such as access to care and chronic stress [6].

Modifiable Risk Factors and What You Can Do About Them

Many brain health risk factors are within your control. Focus on the ones that matter most:

1. Cardiovascular health

High blood pressure, diabetes, and high cholesterol damage blood vessels, reducing blood flow and oxygen delivery to the brain. Because the heart and brain are closely connected, factors that strain the heart can also impair cognitive function and increase dementia risk. Maintaining cardiovascular health is therefore critical for preserving memory and overall brain function [7].

Tip: Manage blood pressure, cholesterol, and diabetes through a balanced diet, regular exercise, and guidance from your healthcare provider.

2. Physical inactivity

Regular movement protects the brain in multiple ways. It boosts blood flow, reduces inflammation, and supports the growth of new neurons, which are all essential for learning and memory. Physical activity also helps maintain a healthy weight, which in turn lowers the risk of cognitive decline [8].

Tip: Aim for a combination of aerobic activity (such as walking or cycling), resistance training, and balance exercises at least 2–3 times a week.

3. Poor diet

Diets high in processed foods, sugar, and unhealthy fats promote inflammation and insulin resistance, both of which can impair brain function. In contrast, eating a diet rich in vegetables, fruits, whole grains, fish, legumes, and healthy fats, such as the Mediterranean, DASH, or MIND diets, is consistently linked to better memory and a lower risk of dementia [9, 10].

Tip: Prioritize vegetables, fruits, whole grains, fish, beans, and healthy fats while limiting processed foods and added sugar.

4. Sleep problems

Deep, restorative sleep allows the glymphatic system to clear beta-amyloid and other waste products from the brain. Chronic sleep deprivation or untreated sleep disorders, such as sleep apnea, disrupt this process, increasing the risk of plaque buildup and cognitive decline [11].

Tip: Aim for 7–9 hours of quality sleep each night and seek evaluation and treatment for sleep disorders.

5. Social isolation and low cognitive engagement

Remaining socially active and mentally stimulated helps build “cognitive reserve,” which enables the brain to resist damage from aging or disease. Conversely, isolation and lack of mental activity can accelerate cognitive decline. Engaging in meaningful relationships and challenging activities keeps the brain resilient [12].

Tip: Maintain friendships, participate in community activities, and regularly engage in new learning opportunities or hobbies.

6. Depression and chronic stress

Prolonged stress and untreated depression increase inflammation and stress hormone levels, which can damage regions of the brain involved in memory and emotional regulation. Managing mental health is therefore essential for protecting cognitive function [13].

Tip: Incorporate stress-reduction practices such as mindfulness, therapy, exercise, or spending time in nature.

7. Smoking and excessive alcohol use

Both smoking and heavy alcohol use are neurotoxic, contributing to inflammation and directly harming neurons. Avoiding these habits is a key step in maintaining brain health.

Tip: Quit smoking and limit alcohol intake to moderate levels to reduce risk.

8. Hearing loss

Untreated hearing loss forces the brain to work harder to process sounds, diverting resources from other cognitive tasks. It also contributes to social withdrawal, which is linked to faster cognitive decline. There are two kinds of hearing loss:

Peripheral hearing loss: reduced ability of your ears to detect sounds, which can often be corrected by hearing aids
Central hearing loss: problems with processing sounds in the brain, which cannot be corrected by hearing aids

While peripheral hearing loss can increase a person’s risk of developing dementia, central hearing loss is often a sign that someone already has Alzheimer’s — it’s one of the earliest reported symptoms.

Tip: Get regular hearing screenings and use hearing aids if needed.

9. Brain injuries

Traumatic brain injuries, including concussions and repeated head trauma, can accelerate cognitive decline and increase the risk of conditions like chronic traumatic encephalopathy (CTE), a progressive neurological disease that leads to dementia and other symptoms such as mood swings and aggression. In its worst stage, CTE requires full-time care, so protecting the brain from injury is vital at any age.

Tip: Wear helmets during sports or high-risk activities, follow safety protocols, and seek prompt medical attention after any head injury.

When to Start Preventing Dementia

The best time to invest in brain health is before symptoms begin. Many of the changes that lead to Alzheimer’s can start 20 years or more before memory problems appear, making midlife (your 40s and 50s) a critical window for prevention. Still, it’s never too late. Positive changes at any age can improve brain health and slow decline.

Examples by life stage:

20s–30s: Build habits of regular exercise (2-3 resistance training sessions and frequent light-to-moderate cardio each week), healthy eating (avoiding processed foods and focusing on plates consisting of high-fiber vegetables and whole grains as well as lean proteins and unsaturated fats), and stress management.
40s–50s: Monitor blood pressure, cholesterol, and blood sugar, and prioritize sleep. Visiting your healthcare provider and staying up-to-date on bloodwork and scans becomes critical to staying attuned to changes in your body. Strength training regimens are also crucial — aging often comes with sarcopenia, a condition where your body’s muscles deteriorate.
60s+: Stay socially engaged, keep learning new skills, and address hearing or vision loss promptly, especially after retirement. Practice daily light exercise to your abilities (walking, swimming, and using a rowing machine are great low-impact ways to exercise) and ensure you’re meeting your daily macronutrient and micronutrient requirements, especially as your appetite decreases.

Using Nouro to Support Long-Term Cognitive Health

While lifestyle is the foundation of dementia prevention, targeted nutritional support can play a complementary role. Nouro is Tonum’s clinically studied brain health supplement, developed in collaboration with Duke Health. It combines natural, science-backed ingredients such as curcumin, resveratrol, green tea extract, and omega-3s that work synergistically to protect the brain.

Clinical research in mice shows that Nouro can:

Help prevent amyloid-beta plaque buildup in the brain (see study)
Boost BDNF (brain-derived neurotrophic factor), which supports neuroplasticity and the growth of new neurons (see study)
Reduce brain inflammation, a driver of cognitive decline (see study)

Nouro is designed for adults who want to protect their long-term cognitive health, whether you’re in midlife and focused on prevention, or later in life and looking to maintain memory and mental sharpness. The supplement is taken daily, making it a simple addition to healthy habits like exercise, sleep, and a balanced diet. Since Nouro can also be used to combat brain fog and improve cognitive function on a day-to-day basis, you can take Nouro even in your 20s and 30s as a cognitive enhancer that simultaneously protects your brain health in the long run.

Takeaways

Alzheimer’s disease and dementia may be complex conditions, but you have more influence over your brain health than you might think. Start by focusing on what you can control: keep your heart healthy, move your body regularly, nourish yourself with a brain-friendly diet, get restorative sleep, and stay socially and mentally engaged. Protect yourself from head injuries, manage stress, and seek support for hearing or mood changes when they arise.

Even small steps, when practiced consistently, can add up to long-term protection. Remember, it’s never too late to begin, your brain can benefit from healthy changes at any age. By investing in your cognitive health today, you’re building a stronger foundation for memory, independence, and quality of life tomorrow.

References:

Liad Stearns, MS, is a health and science writer with a background in neuroscience and functional medicine. She holds a Master’s degree in neuroscience from Tulane University and has professional experience in product development for CGMs and as a functional medicine health coach. Based in San Francisco, Liad specializes in translating complex brain and metabolic health research into clear, actionable content.

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