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How to spot dementia 20 years early

Health & Lifestyle

Dizzy spells in middle age may be a warning sign of dementia 20 years before symptoms appear, research suggests.

Dizzy spells in middle age may be a warning sign of dementia 20 years before symptoms appear, research suggests.

Scientists think sudden drops in blood pressure – often signalled by dizziness when standing up – could cause lasting damage to the brain that raises the risk of dementia.

A study of 11,000 middle-aged people found that those who suffered this problem, known as orthostatic hypotension, were 40 per cent more likely to develop dementia later in life.

Study leader Dr Andreea Rawlings, from the Johns Hopkins Bloomberg School of Public Health in the US, said: “Even though these episodes are fleeting, they may have impacts that are long lasting.

“We found that those people who suffered from orthostatic hypotension in middle age were 40 per cent more likely to develop dementia than those who did not.

“It's a significant finding and we need to better understand just what is happening.”
The team, who presented their findings at the American Heart Association's Lifestyle Scientific Sessions meeting in Oregon, tested 11,503 people aged 45 to 64 for sudden bouts of low blood pressure.

After lying down for 20 minutes, each participant was asked to stand and had his or her blood pressure taken.

Blood pressure is expressed as two numbers, systolic - the upper number - and diastolic - the lower one.

The team diagnosed orthostatic hypotension as a drop of at least 20 points in systolic blood pressure and at least 10 in diastolic blood pressure.

Roughly six per cent of participants were defined with the condition.

They were then tracked for the next 20 years, and found to be 40 per cent more likely to develop dementia than those who had not experienced the same drop in blood pressure.

They also displayed 15 per cent greater rate of cognitive decline in tests.

The researchers said it was not possible to say for certain whether the blood pressure drop was directly linked to dementia or an indicator of some other underlying disease.

But they said even a temporary reduction in blood flow to the brain could have a lasting effect.

Dr Rawlings said: “Identifying risk factors for cognitive decline and dementia is important for understanding disease progression, and being able to identify those most at risk gives us possible strategies for prevention and intervention.

“This is one of those factors worth more investigation.”

Dr Laura Phipps, of Alzheimer's Research UK, said: “While many studies have focused on the risks of high blood pressure, these findings suggest that transient low blood pressure could also have a long term impact on the brain.

“This research adds to a growing and complex picture of how blood pressure changes throughout life can impact the brain.”

Dr James Pickett, head of research at the Alzheimer's Society, added: “Many people experience this form of low blood pressure which can reduce the blood flow to your brain for a short period and result in a dizzy or lightheaded feeling.

“It is not necessarily a cause for concern but people who frequently experience these symptoms should seek advice from their GP. More research is needed to investigate whether treating this kind of low blood pressure would reduce dementia risk.”

Dr Mike Knapton, associate medical director at the British Heart Foundation, said: “It's impossible to say whether the condition is directly causing the development of dementia - however this study will be useful for designing further research to better understand this link.

“People who are being treated for high blood pressure should continue to take their blood pressure medication and should not be put off by this study as this will reduce their risk of having a potentially deadly heart attack or stroke.

“Anyone can reduce their risk of developing dementia, including people with orthostatic hypotension, by stopping smoking, eating a healthier diet and being more physically active.”