A history of high blood pressure that goes untreated is associated with an increased risk of developing dementia. Effective long-term treatment of high blood pressure can reduce dementia risk. All adults, especially once we reach middle age, should have their blood pressure regularly checked by their doctor.
What’s the evidence that blood pressure affects dementia risk?
Research consistently shows that people who have high blood pressure during midlife are on average more likely to develop dementia compared to those with normal blood pressure. The good news is that research also shows treating high blood pressure with appropriate medications can bring this risk down.
In one such study, a group of over 1000 men were followed for around 30 years. The study found that for men with high blood pressure in midlife, the lowest risk of dementia was in those who were treated with medication for over 12 years and whose blood pressure was well controlled by the medication. They had a similar risk to the men with normal blood pressure. The highest risk for dementia was in the men who had high blood pressure but were never treated for it (Peila R, et al. Reducing the risk of dementia: efficacy of long-term treatment of hypertension. Stroke, 2006, 37:1165-1170).
Other studies have shown similar results. High blood pressure can be effectively treated. So to reduce your risk of dementia, stroke and heart disease ask your doctor to regularly check your blood pressure and make sure you follow their treatment advice if it is found to be high.
For older people, it seems that those with low blood pressure may have an increased risk of developing dementia. So whatever your age, regular blood pressure checks are important.
The relationship between blood pressure and dementia risk is complicated.
While not all research findings are consistent, taking the evidence as a whole we can conclude that high blood pressure does increase dementia risk. This has been demonstrated in many observational studies.
Several studies have shown treating high blood pressure is associated with reduced dementia risk.
The evidence suggests that:
- high blood pressure during midlife increases the risk of later developing dementia
- blood pressure decreases as dementia is developing, and low blood pressure at late life is therefore associated with increased incidence of dementia
- low blood pressure may also increase the risk of cognitive decline and dementia through reducing brain blood flow
- treating high blood pressure with antihypertensive medications may reduce the risk of dementia
How does blood pressure affect dementia risk?
Untreated high blood pressure over time can cause damage to blood vessels. This increases the risk of heart disease, stroke and dementia. Your brain needs healthy blood vessels to keep brain cells functioning well.
How to maintain a healthy blood pressure
High intake of salt can increase your blood pressure. Salt is found in almost every food we eat, but most comes from processed foods. High levels of salt often appear in foods such as chips, soups and sauces, baked beans and canned vegetables, processed meats, pizzas and other ready meals or fast food. Check the ‘sodium’ content on the label of foods.
We recommend lowering salt consumption to reduce blood pressure and lower your risk of dementia and cardiovascular disease. Minimise consumption of processed foods and choose ‘low salt’ or ‘no added salt’ varieties. Don’t add salt when cooking or at the table.
Obesity increases the risk of high blood pressure, so it is important to try and maintain a healthy body weight.
Regular physical activity can help reduce your blood pressure.
There are genetic factors that influence your blood pressure, so some people who do all the right things will still have high blood pressure and will need medication to maintain a healthy blood pressure.
The most important thing you can do to make sure your blood pressure stays healthy is to have it checked regularly by your doctor. If your blood pressure is high, follow your doctor’s treatment advice and take any medications as prescribed.
For further information, visit the Heart Foundation website's blood pressure page and download their information sheet.