Older adults whose blood pressure suddenly drops upon standing — a condition called orthostatic hypertension — may be more prone to dementia, according to a new study. The findings were true only for those with a drop in systolic, rather than diastolic, blood pressure or blood pressure overall.

Investigators enrolled 2,131 people who did not have dementia in the study. The average participant age was 73. Blood pressure readings were taken at the outset and then one, three and five years later. Over the next 12 years, 22% of participants developed dementia.

Orthostatic hypotension can result in a dizzy or lightheaded feeling. Study participants whose systolic blood pressure was affected had nearly 40% higher odds of receiving a dementia diagnosis compared with their peers who did not have the condition. When researchers adjusted for other dementia risk factors, such as diabetes, smoking and alcohol use, participants’ risk remained high — at 37%.

In addition, participants whose sitting-to-standing systolic blood pressure readings changed the most between clinic visits were the most likely to develop dementia years later compared with individuals who had relatively stable readings.

Individuals should be screened for orthostatic hypotension, said lead author Laure Rouch, Pharm.D., Ph.D., of the University of California, San Francisco. The condition is not uncommon among adults age 65 and older.

“It’s possible that controlling these blood pressure drops could be a promising way to help preserve people’s thinking and memory skills as they age,” Rouch and colleagues concluded.

The study was published in the journal Neurology.