Introduction
Major cognitive loss, generally labeled dementia, increases with age. Similarly, the fear and anxiety of attaining this state also increases as one ages. Fortunately, about 40% of dementias are preventable. The most recent scientific literature identifies 12 modifiable risk factors convincingly associated with the development of cognitive loss. However, these factors require individual responsibility throughout the life span but undoubtedly are worth the effort as ways to prevent dementia. These modifiable risk factors are discussed in this blog.
To begin with, there are now many types of dementias. Thus, effort is underway to group them into a) severe neurological disorders and b) mild neurological disorders. This has the intended goals of removing the negative connotation of dementia of which the most well known is Alzheimer’s Disease and additionally achieving a more specific diagnosis with tailored treatment for each patient. Further, a diagnosis of mild neurological disorder may encourage lifestyle choices favorable to prevent progression to severe neurological disorder.
Modifiable Risk Factors: relative order of highest to lowest risk
Hearing Impairment Smoking
Depression Low Social Contact
Traumatic Brain Injury Diabetes
Less Education Physical Inactivity
Hypertension Excessive Alcohol Consumption
Obesity (BMI>30) Air Pollution
Ways to Prevent Dementia – comments on modifiable risk factors
1. Hearing Impairment
Hearing loss should be taken seriously as even subclinical loss is related to an increased risk of dementia. Results of a 25 year study showed that those using hearing aids avoided cognitive decline, possibly because untreated hearing impairment reduces brain stimulation facilitating cognitive decline (see blog 16 Age-related hearing loss inadvertently printed with blog 17). Therefore, one of the ways to prevent dementia is to correct hearing impairment.
2. Depression
This condition is associated with an increased risk of dementia. However, the causal factors are poorly defined and it may, in fact, be an early stage of cognitive decline, rather than depression per se. Also whether antidepressant drug use is of benefit in preventing dementia has not been established. Thus, one of the ways to prevent dementia is to evaluate the root cause of depression and with expert help, seek ways to lessen.
3. Traumatic Brain Injury
Severe traumatic brain injury such as skull fracture, bleeds, edema, falls are highly associated with the development of dementia within several years of injury. Risk is related to the severity and number of brain injuries. Therefore, ways to prevent dementia are to avoid high impact sports, improve muscle strength to evade falls and treat cardiovascular disease.
4. Less Education
Because from birth to about twenty years of age, brain growth (new neurons, multiple connections) is optimal, better education during this period yields better protection against cognitive loss in later years. For older individuals, there are a number of studies supporting a “use it or lose it” approach to cognitive maintenance (see Blog 6 positive neuroplasticity). This encompasses, for example, such activities as reading, speaking a second language, physical activity, travel and retiring as late as possible. Computerized training programs have yet to show a significant improvement impact.
5. Hypertension
Elevated systolic blood pressure (>140 mm Hg) midlife (~ 55 years of age) elevates the risk for dementia. If hypertension continues into later years, cognitive loss is further increased. Numerous studies (randomized clinical trials, observational studies) indicate that aggressive lowering of blood pressure (target 120 mm Hg), regardless of the drug class, lowers the risk of dementia. This is the basis for the American Medical Association’s new hypertension guidelines to lower systolic blood pressure below 130 mm Hg in midlife, regardless of the absence of other risk factors. Thus, one of the ways to prevent dementia is to adhere to the AMA guidelines.
6. Obesity
A body mass index (BMI) greater than 30 is highly associated with dementia. This was concluded from 19 longitudinal studies of over five hundred thousand individuals followed for 42 years. There appears to be a benefit on cognitive function with weight loss in individuals with BMI >25 but the evidence needs additional validation. Thus, it is best to maintain a moderate weight to prevent dementia.
7. Smoking
Smokers have increased mortality compared to non smokers so that defining the risk for dementia is challenging and considered biased. However, where there is acceptable data, smoking cessation is beneficial not only on general health but also on reducing the risk of dementia long term. Therefore, one of the ways to prevent dementia is to stop smoking or better yet, never start.
8. Low Social Contact
Systemic and meta-analyses of studies world-wide with long term follow-up (>10 years) support factors such as marital status, associations with family and friends, community group activities and paid work as reducing this risk factor. The effect of this risk factor appears independent of physical health and other lifestyle choices. Intervention with discussion groups may be helpful but needs further evaluation.
9. Diabetes
Type II Diabetes carries a risk of dementia related to the duration and severity of the disease. Unfortunately, it is unknown, at present, which antidiabetic drug is best to prevent cognitive decline. Thus, one of the ways to prevent dementia is to control diabetes with appropriate lifestyle choices and/or medication.
10. Physical Inactivity
In summation of multiple clinical trials (as in meta-analyses), moderate -vigorous aerobic activity (45-60 minutes for multiple days/week) decreased risk of dementia in cognitively stable individuals and improved cognition in those with mild cognitive impairment. Also see Blogs 2-5 on exercise.
11. Excessive Alcohol Intake
It is well established that long term heavy alcohol consumption directly damages the brain and not surprisingly contributes to dementia. On the other hand, light to moderate drinking lessens dementia risk compared to no drinking (generally long term abstinence). Moderate drinking is defined as no more than 21 units (one unit equivalent to10 ml or 8 grams pure alcohol/week). However, debate continues around this as some studies show this cut-off level is too high and should be reduced by as much as 40%. Thus, one of the ways to prevent dementia is to keep alcohol consumption at a low moderate limit.
12. Air Pollution
This risk factor relies heavily on results of animal studies. Particulate air pollutants chemically alter the brain with vascular damage, and negative changes in amyloid and tau protein processes. These changes lead to neurodegeneration. One review of 13 studies assessing 1-15 years exposure to pollutants found that particulate matter, nitrogen dioxide and carbon monoxide played a significant role in promoting cognitive loss. Although challenging, one of the ways to prevent dementia is to avoid areas of known polluted air.
Ways to Prevent Dementia – Role of Diet
Readers may ask whether diet plays a role in prevention of dementia. Scientists agree that it is difficult to accurately quantify individual diets. Nevertheless, epidemiological (observational) studies strongly support the long term adherence to the Mediterranean and the DASH diets (diet high in plant products, nuts, legumes, olive oil and low in saturated fats, meats, salt (see blogs 10 and 11) as associated with reduction in all cause mortality including cardiovascular disease, cancers and Alzheimer’s Disease.
Although clinical trial results disagree, it is concluded that adherence to the Mediterranean-DASH diet significantly reduces hypertension, diabetes and enhances weight loss. Thus, it influences three of the above risk factors. Until the Mediterranean-DASH diet becomes an independent preventive factor in cognitive loss, its influence on defined risk factors for dementia remains important.
Possible Mechanisms
The above risk factors harm the structure and function of the brain. Structural changes of inflammation, aberrant protein deposits e.g. amyloid/tau proteins, and/or vascular damage occur with untreated diabetes, hypertension, traumatic brain injury, smoking, excessive alcohol consumption, air pollution, obesity, physical inactivity and depression. Negative functional brain changes such as loss of or lack of maintenance of cognitive reserve are aggravated by poor childhood education, hearing impairment, low social contact as well as depression, physical inactivity and excessive alcohol intake.
Summary – Ways to Prevent Dementia
The risk factors presented in this blog are fortunately modifiable. This means the responsibility to negate or moderate them falls on the individual. This supports a view expressed repeated in these blogs – the individual is responsible in large part for his/her own aging. Genetics gives one the basic components (organ systems, enzymatic processes, interconnections) but it is up to the individual to maintain them with lifestyle choices that optimize them or seek to avoid negative changes.
If you want to know more about dementia, check out Drug Use In The Older Adult written by myself and Patricia Brown-O’Hara.
References (https://pubmed.ncbi.nlm.nih.gov/)
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5. Rosenau C, Kohler S, Soons LM, Anstey KJ, Brayne C, Brodaty H et al., Umbrella review and Delphi study on modifiable factors for dementia risk reduction. Alzheimer’s Dement. 2024;20:2223–2239.
6. Abbasi J. What to know about the New Blood Pressure Guidelines. JAMA published online Oct 31, 2025. doi: 10.1001/jama2025.17664