If your blood pressure varies greatly from day to day, you may be more likely to develop dementia, according to new research.

Researchers examined how monitoring your blood pressure at home, rather than in the doctor’s office, may affect a person’s dementia risk. In the study, published in the journal Circulation, researchers assessed health data from more than 1,600 older Japanese adults without dementia. For one month, all of the participants measured their blood pressure at home, about three times each morning.

During the following five years, cognitive tests and health records revealed that 134 participants went on to develop Alzheimer’s disease (the most common form of dementia) and 47 subjects developed vascular dementia. After adjusting for various dementia risk factors, the researchers found that those who had the highest variation in systolic blood pressure were more than twice as likely to develop any type of dementia.

Systolic pressure is the top number in your blood pressure reading and it refers to the amount of pressure in your arteries when you heart muscle contracts. The bottom number refers to your blood pressure when your heart rests between beats.

Read: 9 Ways To Prevent Dementia, From Getting More Exercise To Managing Depression

“This research adds to the evidence that blood pressure fluctuations can have serious consequences and highlights the importance of getting frequent, accurate measurements to provide patients with the best treatment plan to prevent those consequences,” Dr. Mary Ann Bauman, an American Heart Association volunteer, said in a statement.

“Further studies are needed to clarify whether day-to-day blood pressure variation is an indicator of future dementia, or whether it might be a target for interventions aimed at preventing dementia,” lead study author Dr. Tomoyuki Ohara, of Kyushu University in Japan, said in a statement.

Read: At-Home Blood Pressure Monitors Give Inaccurate Readings 70% Of The Time, Study Finds

Widely fluctuating blood pressure can be a result of improper treatment, but Ohara points out that other factors may also be to blame. “Mental or physical stress, sleep deprivation, an irregular lifestyle, or damage to nerves that control involuntary bodily functions, can also contribute,” he said.

The researchers chose to assess at-home measurements because they may be more reliable than readings from the doctor’s office. Some patients experience the “white coat effect,” which is when they frequently have a spike in blood pressure while at the doctor’s office, but they don’t experience the same spike at home.

Understanding what factors may contribute to dementia is especially important to study, considering about 47 million people worldwide are living with some form of the condition, according to the World Health Organization. By the year 2030, the number of dementia cases is predicted to jump to about 75 million and by 2050, this number is expected to triple.

See also: Why Visiting Friends With Dementia May Benefit Your Mental Health And Theirs

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