Dementia is a general term that refers to a group of neurodegenerative diseases represented by a cognitive decline. Diseases like Alzheimer’s, these illnesses affect thinking, memory, reasoning, personality, mood and behavior. A variety of factors, including genetics, lifestyle choices, and environmental conditions, influence dementia. Recent research shows that factors other than old age cause dementia-related illnesses, challenging previous beliefs. Regular exercise, consuming less alcohol, and maintaining a healthy weight prevent roughly 40% of dementia cases, according to research.
Newly Discovered Risk factors for Dementia
The Lancet Commission on dementia prevention, intervention, and care has discovered new risk factors related to dementia. Untreated failing eyesight and high LDL cholesterol levels have been linked to increased risk of dementia. This brings the total number of identifiable risk factors for dementia up to 14. Dementia-related illness risk factors can be grouped into two categories, namely modifiable risk factors and non-modifiable risk factors.
Non-Modifiable risk factors for dementia
These risk factors are attributes that cannot be changed or eliminated. These include factors such as age; which is the most significant non-modifiable factor, genetics, family history, gender and ethnicity. However, through proper management strategies such as lifestyle changes and dietary changes, the onset of dementia can be mitigated.
Age
Age is known as the most significant non-modifiable risk factor for dementia-related illness, increasing in risk with age. This is especially exacerbated around the age of 65 and over. Alzheimer’s, which is the most common form of dementia, and its risk doubles approximately every 5 years after the age of 65. Statistically, 2 in every 100 people aged 65 and over develop dementia.
Genetics or Family History
Certain genetic mutations increase the risk of dementia. However, most cases are not always inherited, and it is not necessary for an individual to develop dementia. There are two categories of genes that influence whether someone develops dementia. Firstly, risk genes, which do not always directly cause the onset of dementia, and then deterministic genes. Deterministic genes directly cause dementia, meaning these inherited genes will definitely cause dementia.
Gender
Statistically, women are more likely to develop dementia than men, partly due to longer life expectancy in women. Because age is a major risk factor for developing dementia, and women statistically live longer, they are more susceptible to developing dementia. The most common form of dementia women develop is Alzheimer’s.
Ethnicity
Individuals from certain ethnic backgrounds, particularly black, black Caribbean, and South Asian minority ethnic groups, may have a higher risk of developing dementia. This increased risk is due to the heightened prevalence of hypertension and diabetes. Socio-economic circumstances also contribute to the increased risk of dementia. Lack of access to adequate healthcare, education, and jobs, especially in minority communities, adversely bolsters their risk of developing dementia.
Modifiable Risk Factors for developing dementia
Modifiable risk factors for dementia include risk factors that can be changed or altered to mitigate or potentially reduce the chances of developing dementia. These factors can include lifestyle choices such as limiting alcohol consumption, smoking habits, and physical exercise. In 2020, the Lancet Commission for prevention, intervention and care for dementia suggested that addressing these modifiable risks could delay or prevent dementia cases by 40%.
In 2022, The Lancet Commission published findings that 37% of cases of dementia-related illness were attributed to 8 modifiable risk factors. In 2024, The Lancet Commission added two newly identified modifiable risk factors for developing dementia, namely, untreated vision loss and high LDL cholesterol levels. With this new discovery, the Lancet Commission updated that the prevention of dementia increased to 45% if addressing these 14 modifiable risks.
Smoking
Smoking causes vascular damage as cigarettes contain over 4,700 different chemical compounds, some of which are highly toxic. Studies have demonstrated that individuals who smoke have a higher risk of developing various types of dementia and roughly a 79% chance of developing Alzheimer’s. However, quitting reduces an individual’s risk of developing dementia, and some research has reported no increased risk for former smokers.
Social Isolation
Social isolation may lead to decreased cognitive activity, subsequently leading to cognitive decline and poor mood. It not only increases risks of dementia, but also of hypertension, coronary heart disease, and depression. Social isolation also leads to loneliness, reduced physical activity, and mental stimulation, which increases the risk of developing dementia.
Not Completing Secondary Education
Failing to complete secondary education increases the risk of developing dementia later in life. Research stipulates that individuals with lower educational attainment are more vulnerable to cognitive decline due to reduced “cognitive reserve.” Cognitive reserve refers to the brain’s ability to adapt and maintain function amidst aging or diseases.
Without mental stimulation provided by secondary education, individuals may lack the mental fortitude that works against age-related brain deterioration. Studies have shown that those who engage with learning and cognitive engagement can mitigate the risk of developing dementia.
Type 2 Diabetes
Individuals with type 2 diabetes have a higher risk of developing dementia, particularly when the condition begins in midlife. Research shows that individuals diagnosed with type 2 diabetes earlier in life are more likely to experience dementia at a younger age compared to those diagnosed later. This heightened risk may stem from the longer duration of the disease and the cumulative effects of poorly controlled blood sugar levels over time. Dementia and type 2 diabetes share common traits such as Insulin resistance, vascular complications, inflammation, and oxidative stress. Researchers believe these factors impair brain metabolism and blood flow, contributing to cognitive decline.
Hypertension
Hypertension during midlife increases dementia risk due to vascular damage and inflammation. The damage caused by prolonged high blood pressure, including vascular complications, oxidative stress, and inflammation, can impair brain function over time. However, the evidence remains mixed as with late-life, some people who develop dementia have lower blood pressure than people without dementia.
Obesity
Midlife obesity increases dementia risk by contributing to diabetes, hypertension, and brain inflammation. Obesity is more prevalent in individuals who lack enough physical activity. Healthy lifestyle choices, including weight control, exercise, and balanced diets, reduce Alzheimer ’s-related markers and support cognitive health.
Excessive alcohol consumption
Excessive alcohol consumption significantly increases the risk of developing dementia by damaging brain cells and impairing blood vessel health. This subsequently leads to vascular dementia. Even moderate drinking may pose risks, contrary to earlier protective effects suggested. Heavy alcohol use is linked to changes in brain structures and earlier onset of dementia.
Hearing Loss
Hearing loss increases dementia risk by reducing auditory stimulation and leading to social isolation. Each 10-dB reduction in hearing ability raises dementia risk by a 4% to 24% increase. This connection may stem from hearing loss promoting brain changes linked to dementia or dementia-related changes impairing hearing function. Using hearing aids can lower this risk by improving auditory input, reducing isolation, and supporting brain health, offering an effective strategy for preventing cognitive decline.
Depression
Depression increases dementia risk by affecting brain health. It also elevates stress hormones and hippocampal shrinkage, which is an imperative region of the brain for memory formation. Midlife depression is particularly linked to higher dementia risk. Effective treatment of depression can reduce this risk, highlighting the importance of addressing mental health early to protect against cognitive decline.
Traumatic brain injury
Traumatic brain injury increases dementia risk due to brain damage and neuroinflammation. Brain injuries can be caused by vehicle accidents, sports injuries or severe falls. Severe or repeated TBIs increase the risk of developing dementia significantly. Preventive measures like wearing helmets and seat belts, along with fall prevention strategies, can reduce TBI occurrences and lower the likelihood of developing dementia later in life.
Air Pollution
Studies consistently link exposure to air pollution, particularly fine particulate matter (PM2.5), to an increased risk of dementia and cognitive decline. Researchers worldwide have shown that higher levels of PM2.5 increase the likelihood of developing dementia, estimating that PM2.5 exposure may cause up to 188,000 dementia cases annually. The mechanisms behind this association include chronic inflammation, oxidative stress, and neurodegeneration caused by air pollutants. Air pollution from sources like agriculture and wildfires is particularly concerning, as it contributes significantly to PM2.5 levels.
Physical Inactivity
Exercise improves cognition, blood flow, and promotes the release of a protein that is beneficial for brain cells. Physical activity decreases dementia risk by up to 69%. The WHO recommends at least 150 minutes of moderate activity weekly, emphasizing the importance of consistent movement for maintaining cognitive function.
Untreated Visual Loss
Previously dismissed in 2020 by the Lancet Commission, vision impairment now emerges as a risk factor linked to both cognitive decline and dementia. Recent cohort studies have reported a heightened risk associated with impaired sight, suggesting an underlying connection to illnesses such as diabetes. A US longitudinal study reveals that cataract extraction significantly reduces dementia risk compared to those who don’t undergo the procedure.
High LDL cholesterol
Due to inconclusive evidence, LDL cholesterol was also not considered a risk factor for dementia in the Lancet Commission published in 2020. However, new research published in 2024 reported that high LDL cholesterol in midlife increases the risk of developing dementia. High levels of cholesterol promote vascular damage and inflammation, which can lead to stroke.
High levels of LDL cholesterol also exacerbate the accumulation of amyloid plaques and tau tangles. Amyloid plaques and tau are strongly associated with Alzheimer’s disease.
Addressing Modifiable Risk Factors
Preventing dementia involves addressing modifiable risk factors through personal actions and community-wide initiatives. Individuals can reduce their risk by adopting a healthy lifestyle, including regular exercise, balanced nutrition, avoiding smoking, and limiting alcohol intake. Regular health check-ups to manage blood pressure, cholesterol, and diabetes are essential, as are vision and hearing care to prevent sensory impairments.
On a societal level, public health policies targeting air pollution reduction, education equality, and social isolation are important. Community programs that promote cognitive training, social engagement, and accessible health care further support brain health. Together, these strategies can significantly lower dementia risk globally.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
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