Uncontrolled high blood pressure raises risk of dementia by more than 40%

SINGAPORE – If your blood pressure is high, and you are unable to bring it down through lifestyle changes, take medication, said experts. Otherwise, you face far a higher risk of getting dementia, according to an article in the Journal of the American Medical Association in September.

People with uncontrolled hypertension are 42 per cent more likely to get dementia, while those whose blood pressure is controlled through medication face the same risk as healthy people.

The evidence linking uncontrolled high blood pressure and the risk of getting dementia is strong, given the scope of the study, said Dr Rachel Cheong, a consultant in geriatric medicine at Khoo Teck Puat Hospital.

The article was based on 17 studies of 34,519 people aged between 60 and 110, in 15 countries, including Singapore. None had dementia at the start of the study period.

The study found that taking drugs that lower high blood pressure reduced the risk of getting dementia, compared with people who did not treat their hypertension. This applied to all seniors, no matter their age.

The article concluded that “ongoing antihypertensive therapy throughout late life is an important part of dementia prevention”.

Said Dr Cheong: “The findings suggest that regardless of their age, people with hypertension should be treated, and without treatment, their risk of developing dementia is significantly higher.”

Dr Lim Choon Pin, a private sector cardiologist at The Heart and Vascular Centre, said the study “demonstrates the importance of good blood pressure control in preventing the development of dementia”.

He said many previous studies have shown that treating hypertension can reduce the risk of vascular dementia or Alzheimer’s disease.

There is a well-established link between hypertension and the development of atherosclerosis, or blocked blood vessels, said Dr Lim, who explained that over time hypertension can damage the small blood vessels supplying the brain.

“If it affects the parts of the brain responsible for thinking and memory, it could lead to dementia,” he said.

Dr Lim added that the latest study showed that participants with treated hypertension have similar risks of dementia as healthy individuals and “demonstrates the importance of good blood pressure control in preventing the development of dementia”.

The Ministry of Health guidelines define a normal blood pressure as 130/85mmHg for all age groups.

Added Dr Lim: “ We should aim to keep a blood pressure reading below 140/90mmHg for people below 80 years of age, and 150/90mmHg for people above 80 years old. For people with other medical conditions like kidney diseases or heart diseases, a lower target blood pressure will be recommended.”