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Dizziness from standing up may mean higher risk of dementia

People with orthostatic hypotension in middle age had 54% higher risk of developing dementia

Adrian O'Dowd

Thursday, 26 July 2018

Middle-aged people who feel faint, dizzy or lightheaded when standing up could have a higher risk of developing dementia or stroke later in life, suggests a new study* published in Neurology, the journal of the American Academy of Neurology.

US researchers found an association between this kind of dizziness caused by a sudden drop in blood pressure called orthostatic hypotension and dementia later in life.

Orthostatic hypotension has been linked to heart disease, fainting and falls so researchers led by study author Dr Andreea Rawlings of the Johns Hopkins Bloomberg School of Public Health in Baltimore, USA, set out determine if this form of low blood pressure was also linked to problems in the brain, specifically dementia.

For the study, low blood pressure upon standing was defined as a drop of at least 20 millimetres of mercury (mmHg) in systolic blood pressure, or at least 10 mmHg in diastolic blood pressure.

The study involved 11,709 people with an average age of 54 who were followed for an average of 25 years.

Participants met with researchers up to five times over the course of the study and none of them had a history of heart disease or stroke at the beginning of the study.

During the initial exam, participants were screened for orthostatic hypotension. They were instructed to lie down for 20 minutes and then stand up in a smooth, swift motion. Blood pressure was taken five times upon standing.

The researchers determined the average of the readings and then calculated the difference from the participant’s average resting blood pressure.

They found that 552 participants (4.7%) had orthostatic hypotension at the start of the study.

Participants were monitored throughout the study for dementia and stroke with study visits and by reviewing medical records.

During the study, 1,068 people developed dementia and 842 people had an ischemic stroke.

Analysis showed that those people who had orthostatic hypotension at the beginning of the study had a 54% higher risk of developing dementia than those who did not have orthostatic hypotension at the beginning of the study.

A total of 999 of the 11,156 people without orthostatic hypotension (9%) developed dementia, compared to 69 of the 552 people with orthostatic hypotension (12.5%).

In addition, those with orthostatic hypotension had twice the risk of ischemic stroke.

A total of 15.2% or 84 of 552 people with orthostatic hypotension had an ischemic stroke, compared to 6.8% or 758 of 11,157 people without orthostatic hypotension. There was no association with bleeding strokes.

Dr Rawlings said: “Measuring orthostatic hypotension in middle-age may be a new way to identify people who need to be carefully monitored for dementia or stroke.

“More studies are needed to clarify what may be causing these links as well as to investigate possible prevention strategies.”

A limitation of the study was that orthostatic hypotension was measured only once during the study and may not represent change in blood pressure over time.

*Rawlings, A M, et al. Association of orthostatic hypotension with incident dementia, stroke, and cognitive decline. Neurology Jul 2018, DOI: 10.1212/WNL.0000000000006027.

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