High blood pressure is associated with an increased risk of cognitive impairment later in life, according to a new American Heart Association statement.

Published in the American Heart Association journal Hypertension, the statement is based on multiple studies and explains how high blood pressure influences brain diseases such as stroke, Alzheimer’s disease and vascular cognitive impairment (a range of changes in brain function, from mild to severe, caused by the impaired flow of blood to the brain).

“We know treating high blood pressure reduces the risk of heart diseases such as heart attacks, congestive heart failure and stroke, and it is important to continue treating it to reduce the risks of these diseases,” said Costantino Iadecola, M.D., chair of the writing committee.

“However, we need randomized controlled studies — which prove cause and effect — to determine if treating high blood pressure, especially in middle age, will also decrease the risk of cognitive impairment later in life.”

Most of the clinical trials the writing committee reviewed didn’t directly investigate the effect of high blood pressure on cognition. So they didn’t draft a statement to guide healthcare providers on how to treat patients with dementia.

Years can elapse between when a person has high blood pressure and when the cognitive problems arise. So it’s difficult to address questions such as when to start treatment to protect the brain, the level of blood pressure that should be achieved and which medications are recommended.

Dementia, one of the most common neurological disorders, affects 30 to 40 million people worldwide. The number of people with dementia is anticipated to triple worldwide by 2050 due to the aging of the population, shifts in demography and lack of treatments — with an associated cost exceeding $1.1 trillion.

Alzheimer’s disease and vascular cognitive impairment are the causes for about 80 percent of cognitive impairment cases. Often, patients suffering from dementia have both.

“The SPRINT-MIND trial, a new study that is designed to evaluate the role of treating high blood pressure relative to cognitive impairment, may provide answers to some of the outstanding questions about treating high blood pressure relative to reducing the risk of cognitive impairment,” Iadecola said.

Until then, he recommends treating high blood pressure on an individual basis to protect the brain, heart and kidney.