People who feel lightheaded, dizzy, or faint when standing up may be experiencing a sudden drop in blood pressure called orthostatic hypotension (OH).
Although feeling dizzy sometimes is often not a sign of a serious illness, a new study says middle-aged people who experience such a blood pressure drop may have a greater dementia risk or stroke decades later.
The study of 11,709 people with an average age of 54, none had a history of heart disease or stroke at the beginning of the study, were followed for an average of 25 years by the American Academy of Neurology.
But, at the initial exam, participants were instructed to lie down for 20 minutes and then stand up in a smooth, swift motion. The researchers determined that 552 participants (4.7 percent), had orthostatic hypotension at the start of the study.
During the study, 1,068 people developed dementia and 842 people had an ischemic stroke, which is a stroke where blood flow is blocked to part of the brain.
Researchers found those who had orthostatic hypotension at the beginning of the study had a 54 percent 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 without orthostatic hypotension, or 9 percent, developed dementia, compared to 69 of the 552 people with orthostatic hypotension, or 12.5 percent.
In addition, those with orthostatic hypotension had twice the risk of ischemic stroke. A total of 15.2 percent, or 84 of 552 people, with orthostatic hypotension, had an ischemic stroke, compared to 6.8 percent, or 758 of 11,157 people without orthostatic hypotension. There was no association with bleeding strokes.
“Orthostatic hypotension has been linked to heart disease, fainting and falls, so we wanted to conduct a large study to determine if this form of low blood pressure was also linked to problems in the brain, specifically dementia,” said study author Andreea Rawlings.
“Measuring orthostatic hypotension in middle-age may be a new way to identify people who need to be carefully monitored for dementia or stroke,” said Rawlings. “More studies are needed to clarify what may be causing these links as well as to investigate possible prevention strategies.”
For the study, low blood pressure upon standing was defined as a drop of at least 20 millimeters of mercury (mmHg) in systolic blood pressure, which is the pressure in the blood vessels when the heart beats, or at least 10 mmHg in diastolic blood pressure, the pressure when the heart is at rest. Normal blood pressure is less than 120/80 mmHg.