*Managing your heart health - with lifestyle or medication - can remove their risk from your life.*

A recent systematic review by Dr. Ruth Peters and colleagues found that the the number of heart-related risk factors can determine your risk of dementia (read the full paper here).

This means that for some people it becomes a mathematical certainty that you will develop dementia if you have more than 3 risk factors.

While this may seem like a scary topic, it actually means that if you keep your risk factors low - perhaps even choosing to work towards zero or one that you can’t live without - you might be okay.

In this article we unpack the evidence and provide specific details from the report by Peters et al so that you can decide what action you want to take.

*Sit back and get the facts about dementia risk.*

What is the Highlight?

If you have one risk factor for dementia - let’s say smoking - you aren’t automatically going to get dementia.

However, the more risk factors you have, the more your risk increases.

If you have 3 or more risk factors - such as smoking, lack of exercise, and excess alcohol use - your chances skyrocket by 120%.

Applying the Evidence to You

To know what your risk is, we have to combine the “relative risk” found in this study with your “baseline risk” of dementia.

Most of us are born with a 10% lifetime risk of dementia.

This means that if we have:

1 risk factor = 12% lifetime risk
3 risk factors = 22% lifetime risk

However our baseline risk goes up the longer we live, and by age 85 our risk of having dementia is about 50%.

This means if you are 85 and have

1 risk factor = 60% chance of having dementia
3 risk factors = 110% chance of having dementia, which in practical terms means it is a certainty that you will develop it.

If you want to live a long life and NOT get dementia, you MUST take action to reduce your personal risk factors.

*If you want to enjoy all that life has to offer for a very long time, keep your risk factors at 0-1.*

Who Was Studied?

To find out these results, researchers combined the results from 22 studies involving more than 40,000 people living in 9 different countries.

Patients were followed for at least 22 months and over 20 years in some studies.

*People in 9 different countries were studied, including USA, Sweden, Finland, Netherlands, Germany, France, UK, Australia and Korea.*

What Risk Factors Were Studied?

The main risk factors reported in the studies were those related to your heart-health, including:

high blood pressure
high cholesterol
diabetes
obesity
smoking
low physical activity
poor nutrition

And one risk-factor associated with brain-health:

excessive alcohol intake

Other risk factors less commonly studied included social interaction, medication, depression, education level, and Apo Ɛ4.

*Smoking and other heart-health risk factors were mainly studied.*

What Did They Find?

Studies consistently reported a higher risk of dementia when people had multiple unhealthy lifestyle behaviours, and less risk when they had multiple preventative behaviours.

Specifically, your relative risk for dementia was as follows:

1 risk factor: 20% increased risk (RR 1.20, CI 1.04-1.39)
2 risk factors: 65% increased risk (RR 1.65, CI 1.40-1.94)
3 or more risk factors: 120% increased risk (RR 2.21, CI 1.70 - 2.73).

Remember: this has to be combined with your personal baseline risk - which for most of us is 10% over a lifetime, but 50% over the age of 85.

If you have a family history of dementia, your baseline lifetime risk is already higher, at around 20-40%.

*Having 3 risk factors resulted in 120% increased risk of dementia.*

What about protective factors?

Three of the included studies looked at the relationships between protective factors and dementia, and found that the more healthy things you did, the lower your risk.

However, the studies were too different to be combined into one conclusion, unlike the ones reporting on risk factors, so all we know is that there is a signal that healthy life = less risk (which makes sense).

*As already known, protective factors like exercise are linked to lower risk.*

What do we still not know?

Researchers were not able to figure out whether certain combinations of risk factors led to dementia more than others.

They also did not include all known risk factors such as hearing impairment, depression, social isolation, etc.

We also don’t have a clear sense from this study how protective risk factors can counteract these effects.

No studies looked at the impact of treatment effects on these risk factors, despite the fact that there are good treatments for high blood pressure and diabetes (and a cure for most people with diet and exercise).

*Some of the biggest world-wide causes of dementia like hearing loss (8%), social isolation (4%), and depression (4%), were not included.*

Bottom line: Choose Wisely

The more unhealthy our hearts, the more likely we are to get dementia.
Having 3 or more heart-health risk factors almost guarantees that you will develop dementia if you live to 85.
While any number of risk factors increases our risk, if you must play Russian Roulette with your health, try to keep the number of known risk factors as low as possible - meaning 0 or 1.
We don’t yet know how this combines with other emotional and brain-health risk factors (like hearing, social isolation, depression, education, etc).

Not covered in this article, but known from other research, is that it is the overall balance between strength & damage in the brain that determines whether symptoms of dementia will arise - read more at aldora guides.

How many heart-health risk factors can I have?