14 Ways To Prevent Dementia
Why almost half of all cases of dementia are preventable and what to do about it.
More than heart disease or cancer, the risk of dementia often creates much greater anxiety in the patients I see.
And given that dementia is routinely in the top 5 leading causes of death, this concern is dually warranted.
But can dementia be prevented?
The answer is yes.
But as I have said many, many times in the past, we need to understand that prevention is usually a shorthand way of saying:
“Decrease the odds of something early in life”.
The reason for this is that when it comes to heart disease, cancer and dementia, over a long enough time horizon, even with all the best efforts, you are likely to develop one or all of these conditions at some point.
So, a more precise question would be:
Can we tilt the odds in our favour to avoid getting dementia early in life, and what percentage is avoidable?
The answer is ‘Yes, we can’, and about 45% of all dementia cases are avoidable1.
14 Ways To Prevent Dementia.
Recent data suggests that 14 modifiable factors account for 45% of the future risk of dementia.
This means that controlling these risk factors in our favour should significantly reduce the future risk of dementia.
Not all of these factors are created equal, and when you address these risk factors is also relevant.
The 14 Factors Include:
Hearing Loss
High LDL cholesterol
Less Education
Traumatic Brain Injury
Depression
Social Isolation
Hypertension
Obesity
Smoking
Excess Alcohol
Diabetes
Physical Inactivity
Air Pollution
Visual Loss
Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission
When You Intervene Matters.
As you can see from the graphic, different risk factors impact the risk of dementia at different times.
Addressing visual loss and social isolation are the key factors later in life while addressing education needs matters more early in life.
Most of the factors that can be addressed are best addressed in midlife, between 18 and 65 years of age, and account for over half of the modifiable risk factors.
The earlier you address these, the better.
I would like to focus on 5 of these factors.
Inactivity
Physical activity is one of the best predictors of longevity.
But most people have little interest in living longer if they do not have the cognitive capacity to enjoy that extra time.
Fortunately, physical activity is not only likely to increase the odds of you living longer, it is also very likely to reduce your risk of dementia.
There is a linear relationship between fitness and the risk of dementia.
Compared to those who are the least fit, having a high level of fitness decreases your risk of dementia by 33%2.
This is encouraging, but this study only followed patients for eight years, which is short in terms of dementia risk follow-up.
How about when you evaluate this question over a 44-year time frame?
The impact becomes even greater3.
Compared to a medium fitness level, those in the lowest fitness category had a 41% increase in risk.
This is significant.
But when you compare the highest fitness group to the medium fitness group, the risk of future dementia decreases by 78%.
The risk reduction is obviously even greater when comparing the high and low-fitness groups.
So, if living longer, at a higher quality of life with preserved cognitive capacity is a priority, then exercise has to be on your list.
High Blood Pressure.
It has been long established that high pressure is closely linked to higher rates of dementia.
Persistent systolic blood pressures greater than 140 mmHg during midlife are associated with a doubling in the future risk of dementia4.
The question is whether treating high blood pressure lowers the risk of dementia.
The trials to date have not been definitive in answering this question.
The reason is that dementia risk occurs over a very long time horizon, and therefore, any prospective randomised intervention trial will find it challenging to have a follow-up duration long enough to capture this difference.
As a consequence, we have to rely on post hoc studies and secondary analysis of studies in an attempt to answer this question, which is not ideal.
One such study, which has been presented in meetings but not yet published, suggests that aggressive control of systolic blood pressure down in the 120s range can reduce the future risk of dementia by 15%5.
However, this data is broadly consistent with other similar studies with effect sizes of a 13% reduction in dementia risk with good blood pressure control6.
What seems clear is that blood pressure lowering with medications is probably effective at lowering the future risk of dementia, but a far better strategy is close attention to lifestyle factors that prevent the appearance of high blood pressure in the first place.
Diabetes & Insulin Resistance
Type 2 diabetes is when insulin resistance reaches the point where blood sugar levels can no longer be kept in range.
We need to think of these conditions not as separate entities but as existing along a continuum.
Both of these conditions, however, are preventable with appropriate attention to the standard lifestyle factors of nutrition and exercise.
There is undoubtedly a genetic component to the risk of diabetes, but it can at least be delayed until later in life.
Having diabetes increases the risk of any type of dementia by 73%7.
Insulin resistance also increases the risk of dementia, but interestingly, it seems to act as a force multiplier of risk if you are a carrier of the APOE 4 gene variant, which is one of the primary genetic risk factors for late-onset dementia.
Those with APOE 4 gene variants have an increased risk of dementia, but in the presence of insulin resistance, that risk is magnified8.
Obesity
The relationship between obesity and dementia is not straightforward and likely depends on when a person becomes obese and also whether there is significant metabolic dysfunction with the obesity.
However, obesity in midlife is associated with a 39% increase in risk of dementia later in life9.
So we know that avoiding obesity is likely to reduce the risk of dementia, but like high blood pressure, the question is, is treating obesity going to reduce that risk?
The answer here is maybe10.
Recent observational studies have suggested a 20 to 30% reduction in the future risk of dementia with treatment using the GLP-1 medication class of medications that you will commonly know as Ozempic, etc.
While this data is encouraging, it is by no means definitive. When the curves for such a response separate right from the very start of the study, you have to question whether selection biases are more likely to be driving the effect than the drug therapy.
However, I have no doubt that a prospective randomised study will be conducted in the future to answer this question.
High LDL Cholesterol.
The last time the Lancet published its findings on preventable factors for dementia was in 2020, and the estimated figure was 40%.
This has now increased to 45%, and most of that increase has been driven by the addition of high LDL cholesterol as a modifiable risk factor for dementia.
Higher levels of LDL cholesterol and ApoB have been linked to an increased risk of dementia11.
The question that routinely arises is the relationship between lowering LDL cholesterol and dementia.
There is no compelling evidence to suggest that lowering LDL cholesterol to even very low levels increases the risk of dementia. I have discussed this at length in a previous article here.
In fact, there is growing evidence to support the use of lipid-lowering therapies in reducing the risk of dementia1213.
While definitive trials have not been conducted to answer this question, we can say with a very high degree of confidence that avoiding lifelong high LDL cholesterol or ApoB concentrations is a good thing and that cholesterol-lowering therapy is unlikely to be a bad thing.
14 Ways To Prevent Dementia.
While there is no 100% way to avoid dementia, there is a LOT that can be done to avoid a bump in future risk, and most of these approaches rely on close attention to the core lifestyle factors of nutrition, exercise, sleep and cognitive well-being, particularly in midlife.
You might have to worry more about correcting visual and hearing loss later in life, but for most people, getting the basics right in midlife will get them most of the way there.
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Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet. 2024 Jul 30:S0140-6736(24)01296-0.
Cardiorespiratory fitness and risk of Alzheimer's disease and related dementias among American veterans. Alzheimers Dement. 2023 Mar 22.
Midlife cardiovascular fitness and dementia: A 44-year longitudinal population study in women. Neurology. 2018 Apr 10;90(15):e1298-e1305.
Blood pressure from mid- to late life and risk of incident dementia. Neurology. 2017 Dec 12;89(24):2447-2454.
https://www.medscape.com/viewarticle/998381
Dementia rIsk REduCTion (DIRECT) collaboration, Blood pressure lowering and prevention of dementia: an individual patient data meta-analysis, European Heart Journal, Volume 43, Issue 48, 21 December 2022, Pages 4980–4990
Diabetes mellitus and risk of dementia: A meta-analysis of prospective observational studies. J Diabetes Investig. 2013 Nov 27;4(6):640-50.
Midlife insulin resistance, APOE genotype, and late-life brain amyloid accumulation. Neurology® 2018;90:e1150-e1157
Midlife and late-life obesity and the risk of dementia: cardiovascular health study. Arch Neurol. 2009 Mar;66(3):336-42.
Comparative effectiveness of glucagon-like peptide-1 agonists, dipeptidyl peptidase-4 inhibitors, and sulfonylureas on the risk of dementia in older individuals with type 2 diabetes in Sweden: an emulated trial study. EClinical Medicine. June 20. 2024.
Mendelian randomization reveals apolipoprotein B shortens healthspan and possibly increases risk for Alzheimer’s disease.Commun Biol 7, 230 (2024).
Statin exposure and the risk of dementia in individuals with hypercholesterolaemia. J Intern Med. 2020 Dec;288(6):689-698.
Statins and risks of dementia among patients with heart failure: a population-based retrospective cohort study in Hong Kong. Lancet Reg Health West Pac. 2024 Jan 17;44:101006.